7,500,000 Firm Shares of Common Stock Par value $0.001 per share 1,125,000 Option Shares of Common Stock ENDEAVOUR INTERNATIONAL CORPORATION Underwriting Agreement

Exhibit 1.1

Execution Copy

7,500,000 Firm Shares of Common Stock

Par value $0.001 per share

1,125,000 Option Shares of Common Stock

ENDEAVOUR INTERNATIONAL CORPORATION

Underwriting Agreement

June 13, 2012

Global Hunter Securities, LLC

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Ladies and Gentlemen:

Endeavour International Corporation, a Nevada corporation (the “Company”), proposes to sell to the Underwriter named in Schedule II hereto (the “Underwriter”) the number of shares of common stock, $0.001 par value per share (“Common Stock”), of the Company set forth in Schedule I hereto (the “Firm Shares”). The Company also proposes to grant to the Underwriter an option to purchase up to the number of additional shares of Common Stock set forth in Schedule I hereto to cover over-allotments, if any (the “Option Shares”; the Option Shares, together with the Firm Shares, being hereinafter called the “Shares”). Any reference herein to the Registration Statement, the Base Prospectus, any Preliminary Prospectus or the Final Prospectus shall be deemed to refer to and include the documents incorporated by reference therein pursuant to Item 12 of Form S-3 which were filed under the Exchange Act on or before the Effective Date of the Registration Statement or the issue date of the Base Prospectus, any Preliminary Prospectus or the Final Prospectus, as the case may be (“Incorporated Documents”); and any reference herein to the terms “amend,” “amendment” or “supplement” with respect to the Registration Statement, the Base Prospectus, any Preliminary Prospectus or the Final Prospectus shall be deemed to refer to and include the filing of any document under the Exchange Act after the Effective Date of the Registration Statement or the issue date of the Base Prospectus, any Preliminary Prospectus or the Final Prospectus, as the case may be, deemed to be incorporated therein by reference. Certain terms used herein are defined in Section 20 hereof.

1. Representations and Warranties. The Company represents and warrants to, and agrees with, the Underwriter as set forth below in this Section 1.

(a) The Company meets, and as of each Effective Date met, the requirements for use of Form S-3 under the Act and has prepared and filed with the Commission a registration statement (the file number of which is set forth in Schedule I hereto) on Form S-3, including a related Base Prospectus, for registration under the Act of the offering and sale of the Shares. Such Registration Statement, including any amendments thereto filed prior to the Execution Time, has become effective under the Act. The

Company has filed with the Commission, as part of an amendment to the Registration Statement or pursuant to Rule 424(b), one or more preliminary prospectus supplements relating to the Shares, each of which has previously been furnished to you. The Company will file with the Commission a final prospectus supplement relating to the Shares in accordance with Rule 424(b). As filed, such final prospectus supplement shall contain all information required by the Act and the rules thereunder, and, except to the extent the Underwriter shall agree in writing to a modification, shall be in all substantive respects in the form furnished to you prior to the Execution Time or, to the extent not completed at the Execution Time, shall contain only such specific additional information and other changes (beyond that contained in the Base Prospectus and any Preliminary Prospectus) as the Company has advised you, prior to the Execution Time, will be included or made therein. The Registration Statement, at the Execution Time, meets the requirements set forth in Rule 415(a)(1)(x). The initial Effective Date of the Registration Statement was not earlier than the date three years before the Execution Time.

(b) On each Effective Date, the Registration Statement did, and when the Final Prospectus is first filed in accordance with Rule 424(b) and on the Closing Date (as defined herein) and on any date on which Option Shares are purchased, if such date is not the Closing Date (a “settlement date”), the Final Prospectus (and any supplement thereto and including the Incorporated Documents) will, comply in all material respects with the applicable requirements of the Act and the Exchange Act and the respective rules thereunder; on each Effective Date, the Registration Statement did not and will not contain any untrue statement of a material fact or omit to state any material fact required to be stated therein or necessary in order to make the statements therein not misleading; and on the date of any filing pursuant to Rule 424(b) and on the Closing Date and any settlement date, the Final Prospectus (together with any supplement thereto and including the Incorporated Documents) will not include any untrue statement of a material fact or omit to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading; provided, however, that the Company makes no representations or warranties as to the information contained in or omitted from the Registration Statement or the Final Prospectus (or any supplement thereto) in reliance upon and in conformity with information furnished in writing to the Company by the Underwriter specifically for inclusion in the Registration Statement or the Final Prospectus (or any supplement thereto), it being understood and agreed that the only such information furnished by the Underwriter consists of the information described as such in Section 8 hereof.

(c) None of (i) the Disclosure Package and the price to the public, the number of Firm Shares and the number of Option Shares to be included on the cover page of the Final Prospectus, when taken together as a whole, or (ii) each electronic road show when taken together as a whole with the Disclosure Package and the price to the public, the number of Firm Shares and the number of Option Shares to be included on the cover page of the Final Prospectus, contains any untrue statement of a material fact or omit to state any material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading. The preceding sentence does not apply to statements in or omissions from the foregoing based upon and in conformity with written information furnished to the Company by or on behalf of the

Underwriter specifically for use therein, it being understood and agreed that the only such information furnished by the Underwriter consists of the information described as such in Section 8 hereof.

(d) (i) At the earliest time after the filing of the Registration Statement that the Company or another offering participant made a bona fide offer (within the meaning of Rule 164(h)(2)) of the Shares and (ii) as of the Execution Time (with such date being used as the determination date for purposes of this clause (ii)) the Company was not and is not an Ineligible Issuer (as defined in Rule 405), without taking account of any determination by the Commission pursuant to Rule 405 that it is not necessary that the Company be considered an Ineligible Issuer.

(e) Each Issuer Free Writing Prospectus does not include any information that conflicts with the information contained in the Registration Statement, including any Incorporated Document and any prospectus supplement deemed to be a part thereof that has not been superseded or modified. The foregoing sentence does not apply to statements in or omissions from any Issuer Free Writing Prospectus based upon and in conformity with written information furnished to the Company by the Underwriter specifically for use therein, it being understood and agreed that the only such information furnished by or on behalf of the Underwriter consists of the information described as such in Section 8 hereof.

(f) Each of the Company and its Subsidiaries has been duly formed or organized, as the case may be, and is validly existing in good standing (in the case of foreign subsidiaries, such analogous concept) under the laws of the jurisdiction in which it is chartered or organized with full power and authority to own or lease, as the case may be, and to operate its properties and conduct its business as described in the Disclosure Package and the Final Prospectus, and is duly qualified to do business and is in good standing under the laws of each jurisdiction which requires such qualification, except for such jurisdictions where the failure to so qualify or to be in good standing would not, individually or in the aggregate, result in a Material Adverse Effect.

(g) All the outstanding shares of capital stock (or corresponding equity interest) of each Subsidiary have been duly and validly authorized and issued and are fully paid and nonassessable, and, except as otherwise set forth in the Disclosure Package and the Final Prospectus and except as arise under or pursuant to the credit agreement dated April 12, 2012 among the Company, Endeavour Energy UK Limited, Cyan Partners, LP and various lenders listed therein (the “Credit Agreement”), all outstanding shares of capital stock (or corresponding equity interest) of the Subsidiaries are owned by the Company either directly or through wholly owned Subsidiaries free and clear of any perfected security interest or any other security interests, claims, liens or encumbrances.

(h) There is no contract or other document of a character required to be described in the Registration Statement or Final Prospectus, or to be filed as an exhibit thereto, which is not described or filed as required (and the Preliminary Prospectus contains in all material respects the same description of the foregoing matters contained in the Final Prospectus); and the descriptions of statutes, legal, governmental and

regulatory proceedings and contracts and other documents insofar as such descriptions summarize legal matters, agreements, documents or proceedings discussed therein, are accurate and fair descriptions of such legal matters, agreements, documents or proceedings in all material respects.

(i) This Agreement has been duly authorized, executed and delivered by the Company.

(j) The authorized capital stock of the Company conforms to the description thereof contained in the Disclosure Package and the Final Prospectus in all material respects.

(k) The Company is not and, after giving effect to the offering and sale of the Shares and the application of the proceeds thereof as described in the Disclosure Package and the Final Prospectus, will not be, an “investment company” as defined in the Investment Company Act of 1940, as amended.

(l) No consent, approval, authorization, filing with or order of any court or governmental agency or body is required in connection with the transactions contemplated herein, except such as have been obtained under the Act and such as may be required by the Financial Industry Regulatory Authority, Inc. (“FINRA”) and under the blue sky laws of any jurisdiction in connection with the purchase and distribution of the Shares by the Underwriter in the manner contemplated herein and in the Disclosure Package and the Final Prospectus.

(m) Neither the issuance and sale of the Shares nor the consummation of any other of the transactions herein contemplated nor the application of the proceeds therefrom as set forth in the Disclosure Package nor the fulfillment of the terms hereof will conflict with, require any consent under, result in a breach or violation of, or imposition of any lien, charge or encumbrance upon any property or assets of the Company or any of its Subsidiaries pursuant to, (i) the organizational documents of the Company or any of its Subsidiaries, (ii) the terms of any indenture, contract, lease, mortgage, deed of trust, note agreement, loan agreement or other agreement, obligation, condition, covenant or instrument to which the Company or any of its Subsidiaries is a party or bound or to which its or their property is subject, or (iii) any statute, law, rule, regulation, judgment, order or decree applicable to the Company or any of its Subsidiaries of any court, regulatory body, administrative agency, governmental body, arbitrator or other authority having jurisdiction over the Company or any of its Subsidiaries or any of its or their properties, except, with respect to clauses (ii) and (iii) only, for such defaults or violations as would not, individually or in the aggregate, result in a Material Adverse Effect.

(n) Except as set forth in the Disclosure Package and the Final Prospectus, there are no preemptive rights or other rights to subscribe for or to purchase, nor any restriction upon the voting or transfer of, any shares of capital stock of the Company. No holders of securities of the Company have rights to the registration of such securities

under the Registration Statement or as a result of the transactions contemplated under this Agreement.

(o) The consolidated historical financial statements and schedules of the Company and its consolidated Subsidiaries included in the Preliminary Prospectus, the Final Prospectus and the Registration Statement present fairly the financial condition, results of operations and cash flows of the Company as of the dates and for the periods indicated, comply as to form in all material respects with the applicable accounting requirements of the Act and have been prepared in conformity with generally accepted accounting principles applied on a consistent basis throughout the periods involved (except as otherwise noted therein); and the pro forma financial information and the related notes thereto included or incorporated by reference in the Preliminary Prospectus, the Final Prospectus and the Registration Statement have been prepared in accordance with the applicable requirements of the Act and the Exchange Act, as applicable, and the assumptions underlying such pro forma financial information are reasonable and are set forth in the Preliminary Prospectus, the Final Prospectus and the Registration Statement. The selected financial data set forth under the caption “Summary Consolidated Historical Financial Data” in the Preliminary Prospectus, the Final Prospectus and Registration Statement fairly present, on the basis stated in the Preliminary Prospectus, the Final Prospectus and the Registration Statement, the information included therein. The other financial, reserve and statistical data contained or incorporated by reference in the Registration Statement, the Preliminary Prospectus and the Final Prospectus (and any amendment or supplement thereto) are accurately and fairly presented and prepared on a basis consistent with the financial statements and books and records of the Company and its Subsidiaries.

(p) As of March 31, 2012, the Company had or would have had, on the consolidated historical and pro forma as adjusted basis indicated in the Disclosure Package and the Final Prospectus, a pro-forma capitalization as set forth therein under the heading “Capitalization.”

(q) No action, suit or proceeding by or before any court or governmental agency, authority or body or any arbitrator involving the Company or any of its Subsidiaries or its or their property is pending or, to the best knowledge of the Company, threatened that could reasonably be expected to (A) have a material adverse effect on the condition (financial or otherwise), prospects, earnings, business or properties of the Company and its Subsidiaries, taken as a whole, whether or not arising from transactions in the ordinary course of business or (B) prevent or materially interfere with the ability of the Company to perform this Agreement or consummate the transactions contemplated hereby (the occurrence of any such effect or any such prevention or interference or any such result described in the foregoing clauses (A) and (B) being herein referred to as a “Material Adverse Effect”), except as set forth in or contemplated in the Disclosure Package and the Final Prospectus (exclusive of any supplement thereto).

(r) Each of the Company and its Subsidiaries owns or leases all such properties as are necessary to the conduct of its operations as presently conducted or to be conducted on the Closing Date or settlement date.

(s) Neither the Company nor any Subsidiary is in violation or default of (i) any provision of its organizational documents, (ii) the terms of any indenture, contract, lease, mortgage, deed of trust, note agreement, loan agreement or other agreement, obligation, condition, covenant or instrument to which it is a party or bound or to which its property is subject, or (iii) any statute, law, rule, regulation, judgment, order or decree of any court, regulatory body, administrative agency, governmental body, arbitrator or other authority having jurisdiction over the Company or such Subsidiary or any of its properties, as applicable, except, with respect to clauses (ii) and (iii) only, for such defaults or violations as would not, individually or in the aggregate, result in a Material Adverse Effect.

(t) KPMG LLP, who has certified certain audited financial statements of the Company and its subsidiaries, is an independent registered public accounting firm with respect to the Company and its subsidiaries within the applicable rules and regulations adopted by the Commission and the Public Company Accounting Oversight Board (United States) and as required by the Act. Ernst & Young LLP, who has reviewed the Company’s first quarter financial statements for 2012, is an independent registered public accounting firm with respect to the Company and its subsidiaries within the applicable rules and regulations adopted by the Commission and the Public Company Accounting Oversight Board (United States) and as required by the Act.

(u) Each of the Company and its Subsidiaries has filed all tax returns that are required to be filed or has requested extensions thereof (except in any case in which the failure so to file would not have a Material Adverse Effect and except as set forth in or contemplated in the Disclosure Package and the Final Prospectus (exclusive of any supplement thereto), and has paid all taxes required to be paid by it and any other assessment, fine or penalty levied against it, to the extent that any of the foregoing is due and payable, except for any such assessment, fine or penalty that is currently being contested in good faith or as would not have a Material Adverse Effect, except as set forth in or contemplated in the Disclosure Package and the Final Prospectus (exclusive of any supplement thereto).

(v) No labor problem or dispute with the employees of the Company or any of its Subsidiaries exists or to the best knowledge of the Company, is threatened or imminent, and the Company is not aware of any existing or imminent labor disturbance by the employees of any of its or its Subsidiaries’ principal suppliers, contractors or customers, that would have a Material Adverse Effect, except as set forth in or contemplated in the Disclosure Package and the Final Prospectus (exclusive of any supplement thereto).

(w) Netherland, ▇▇▇▇▇▇ & Associates, Inc. (“NSA”), who issued a report with respect to the Company’s oil and natural gas reserves at December 31, 2011, 2010 and 2009, and with respect to the oil reserves at December 31, 2011 regarding the assets (the “COP Assets”) to be acquired pursuant to the Sale and Purchase Agreement between ConocoPhillips (U.K. Limited), ConocoPhillips Petroleum Limited, ConocoPhillips (U.K.) Lambda Limited and Endeavour Energy UK Limited dated as of December 23, 2011, and who has delivered the proved reserve letter referred to in Section 6(e) hereof, was, as of the date of such report, and is, as of the date hereof, an independent petroleum engineer with respect to the Company.

(x) The oil and gas reserve estimates of the Company at December 31, 2011, 2010 and 2009 and of the COP Assets at December 31, 2011 contained or incorporated by reference in the Registration Statement, the Disclosure Package and the Final Prospectus were prepared by or audited by NSA; such reserve estimates fairly reflect, in all material respects, the oil and gas reserves of the Company and of the COP Assets at the dates indicated therein and are in accordance with the Commission guidelines applicable thereto applied on a consistent basis throughout the periods involved.

(y) The organizational documents of the Company and each of its Subsidiaries have been duly authorized, executed and delivered by the Company or such Subsidiary, as the case may be, and are enforceable against the respective parties thereto in accordance with their terms; provided that the enforceability thereof may be limited by (A) bankruptcy, insolvency, fraudulent transfer, reorganization, moratorium and similar laws relating to or affecting creditors’ rights generally and by general principles of equity (regardless of whether such enforceability is considered in a proceeding in equity or at law) and (B) public policy, applicable law relating to fiduciary duties and indemnification and contribution and an implied covenant of good faith and fair dealing.

(z) The Company and each of its Subsidiaries are insured by insurers of recognized financial responsibility against such losses and risks and in such amounts as are customary in the businesses in which they are engaged; all policies of insurance insuring the Company or any of its Subsidiaries or their respective businesses, assets, employees, officers and directors are in full force and effect; the Company and its Subsidiaries are in compliance with the terms of such policies and instruments in all material respects; and there are no claims by the Company or any of its Subsidiaries under any such policy or instrument as to which any insurance company is denying liability or defending under a reservation of rights clause; neither the Company nor any such Subsidiary has been refused any insurance coverage sought or applied for; and neither the Company nor any such Subsidiary has any reason to believe that it will not be able to renew its existing insurance coverage as and when such coverage expires or to obtain similar coverage from similar insurers as may be necessary to continue its business at a cost that would not have a Material Adverse Effect, except as set forth in or contemplated in the Disclosure Package and the Final Prospectus (exclusive of any supplement thereto).

(aa) No Subsidiary is currently prohibited, directly or indirectly, from paying any dividends to the Company, from making any other distribution on such Subsidiary’s capital stock (or corresponding equity interest), from repaying to the Company any loans or advances to such Subsidiary from the Company or from transferring any of such Subsidiary’s property or assets to the Company or any other Subsidiary of the Company, except as described in or contemplated by the Disclosure Package and the Final Prospectus (exclusive of any supplement thereto).

(bb) The Company and its Subsidiaries possess all licenses, certificates, permits and other authorizations issued by all applicable authorities necessary to conduct their respective businesses, and neither the Company nor any such Subsidiary has received any notice of proceedings relating to the revocation or modification of any such license, certificate, authorization or permit which, singly or in the aggregate, if the subject of an unfavorable decision, ruling or finding, would have a Material Adverse Effect, except as set forth in or contemplated in the Disclosure Package and the Final Prospectus (exclusive of any supplement thereto).

(cc) The Company and each of its Subsidiaries maintain a system of internal accounting controls sufficient to provide reasonable assurance that (i) transactions are executed in accordance with management’s general or specific authorizations; (ii) transactions are recorded as necessary to permit preparation of financial statements in conformity with generally accepted accounting principles and to maintain asset accountability; (iii) access to assets is permitted only in accordance with management’s general or specific authorization; and (iv) the recorded accountability for assets is compared with the existing assets at reasonable intervals and appropriate action is taken with respect to any differences. The Company and its Subsidiaries’ internal controls over financial reporting are effective, and the Company and its Subsidiaries are not aware of any material weakness in their internal controls over financial reporting.

(dd) The Company and its Subsidiaries maintain “disclosure controls and procedures” (as such term is defined in Rule 13a-15(e) under the Exchange Act); such disclosure controls and procedures are effective.

(ee) The Company has not taken, directly or indirectly, any action designed to or that would constitute or that could reasonably be expected to cause or result in, under the Exchange Act or otherwise, stabilization or manipulation of the price of any security of the Company to facilitate the sale or resale of the Shares.

(ff) Since March 31, 2012, none of the Company or its Subsidiaries has sustained any material loss or interference with its business from fire, explosion, flood or other calamity, whether or not covered by insurance, or from any labor dispute or court or governmental action, investigation, order or decree, otherwise than as set forth or contemplated in the Disclosure Package and the Final Prospectus. Except as disclosed in the Disclosure Package and the Final Prospectus (or any amendment or supplement thereto), subsequent to the respective dates as of which such information is given in the Disclosure Package and the Final Prospectus (or any amendment or supplement thereto), (i) none of the Company or its Subsidiaries has incurred any liability or obligation, indirect, direct or contingent, or entered into any transactions, not in the ordinary course of business, that, individually or in the aggregate, is material to the Company and its Subsidiaries, taken as a whole, (ii) there has not been any material change in the capitalization or material increase in the short-term debt or long-term debt of the Company or its Subsidiaries and (iii) there has not been any material adverse change, or any development involving, individually or in the aggregate, a prospective material adverse change in or affecting the general affairs, condition (financial or other), business, prospects, assets or results of operations of the Company and its Subsidiaries.

(gg) The Company and its Subsidiaries are (i) in compliance with any and all applicable foreign, federal, state and local laws (including common law), statutes, ordinances, rules, orders, judgments, decrees, permits, license registration, exemptions, approvals, authorization and regulations relating to the generation, use, treatment, storage, handling, transportation and disposal of hazardous or toxic substances, pollutants or contaminants, materials or wastes or the protection of human health and safety (to the extent such health and safety relate to exposure to hazardous or toxic substances, materials or wastes) or the environment which are applicable to their businesses (“Environmental Laws”), (ii) have received and are in compliance with all permits, licenses or other approvals required of them under applicable Environmental Laws to conduct their respective businesses and (iii) have not received notice of any actual or potential liability under any environmental law, except where such non-compliance with Environmental Laws, failure to receive required permits, licenses or other approvals, or liability would not, individually or in the aggregate, have a Material Adverse Effect, except as set forth in or contemplated in the Disclosure Package and the Final Prospectus (exclusive of any supplement thereto). Except as set forth in the Disclosure Package and the Final Prospectus, neither the Company nor any of the Subsidiaries has been named as a “potentially responsible party” under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980, as amended.

(hh) In the ordinary course of its business, the Company periodically reviews the effect of Environmental Laws on the business, operations and properties of the Company and its Subsidiaries, in the course of which it identifies and evaluates associated costs and liabilities (including, without limitation, any capital or operating expenditures required for clean-up, closure of properties or compliance with Environmental Laws, or any permit, license or approval, any related constraints on operating activities and any potential liabilities to third parties). On the basis of such review, the Company has reasonably concluded that such associated costs and liabilities would not, singly or in the aggregate, have a Material Adverse Effect, except as set forth in or contemplated in the Disclosure Package and the Final Prospectus (exclusive of any supplement thereto).

(ii) None of the following events has occurred or exists: (i) a failure to fulfill the obligations, if any, under the minimum funding standards of ▇▇▇▇▇▇▇ ▇▇▇ ▇▇ ▇▇▇ ▇▇▇▇▇▇ ▇▇▇▇▇▇ Employee Retirement Income Security Act of 1974, as amended (“ERISA”), and the regulations and published interpretations thereunder with respect to a Plan, determined without regard to any waiver of such obligations or extension of any amortization period; (ii) an audit or investigation by the Internal Revenue Service, the U.S. Department of Labor, the Pension Benefit Guaranty Corporation or any other federal or state governmental agency or any foreign regulatory agency with respect to the employment or compensation of employees by any of the Company or any of its Subsidiaries that could have a Material Adverse Effect; (iii) any breach of any contractual obligation, or any violation of law or applicable qualification standards, with respect to the employment or compensation of employees by the Company or any of its Subsidiaries that could have a Material Adverse Effect. None of the following events has occurred or is reasonably likely to occur: (i) a material increase in the aggregate amount

of contributions required to be made to all Plans in the current fiscal year of the Company and its Subsidiaries compared to the amount of such contributions made in the most recently completed fiscal year of the Company and its Subsidiaries; (ii) a material increase in the “accumulated post-retirement benefit obligations” (within the meaning of Statement of Financial Accounting Standards 106) of the Company and its Subsidiaries compared to the amount of such obligations in the most recently completed fiscal year of the Company and its Subsidiaries; (iii) any event or condition giving rise to a liability under Title IV of ERISA that could have a Material Adverse Effect; or (iv) the filing of a claim by one or more employees or former employees of the Company or any of its Subsidiaries related to their employment that could have a Material Adverse Effect. For purposes of this paragraph, the term “Plan” means a plan (within the meaning of Section 3(3) of ERISA) subject to Title IV of ERISA with respect to which the Company or any of its Subsidiaries may have any liability.

(jj) There is and has been no failure on the part of the Company and any of the Company’s directors or officers, in their capacities as such, to comply with any provision of the ▇▇▇▇▇▇▇▇-▇▇▇▇▇ Act of 2002 and the rules and regulations promulgated in connection therewith, including Section 402 relating to loans and Sections 302 and 906 relating to certifications.

(kk) Neither the Company nor any of its Subsidiaries nor, to the knowledge of the Company, any director, officer, agent, employee or affiliate of the Company or any of its Subsidiaries is aware of or has taken any action, directly or indirectly, that would result in a violation by such persons of the Foreign Corrupt Practices Act of 1977, as amended, and the rules and regulations thereunder (the “FCPA”), including, without limitation, making use of the mails or any means or instrumentality of interstate commerce corruptly in furtherance of an offer, payment, promise to pay or authorization of the payment of any money, or other property, gift, promise to give, or authorization of the giving of anything of value to any “foreign official” (as such term is defined in the FCPA) or any foreign political party or official thereof or any candidate for foreign political office, in contravention of the FCPA; and the Company, its Subsidiaries and, to the knowledge of the Company, its affiliates, have conducted their businesses in compliance with the FCPA and have instituted and maintain policies and procedures designed to ensure, and which are reasonably expected to continue to ensure, continued compliance therewith.

(ll) The operations of the Company and its Subsidiaries are and have been conducted at all times in compliance with applicable financial recordkeeping and reporting requirements and the money laundering statutes and the rules and regulations thereunder and any related or similar rules, regulations or guidelines, issued, administered or enforced by any governmental agency (collectively, the “Money Laundering Laws”) and no action, suit or proceeding by or before any court or governmental agency, authority or body or any arbitrator involving the Company or any of its Subsidiaries with respect to the Money Laundering Laws is pending or, to the knowledge of the Company, threatened.

(mm) Neither the Company nor any of its Subsidiaries nor, to the knowledge of the Company, any director, officer, agent, employee or affiliate of the Company or any of its Subsidiaries is currently subject to any sanctions administered by the Office of Foreign Assets Control of the U.S. Treasury Department (“OFAC”); and the Company will not directly or indirectly use the proceeds of the offering, or lend, contribute or otherwise make available such proceeds to any Subsidiary, joint venture partner or other person or entity, for the purpose of financing the activities of any person currently subject to any U.S. sanctions administered by OFAC.

(nn) The Subsidiaries, after excluding Endeavour Operating Corporation, a Delaware corporation (“Endeavour Operating”), and Endeavour Energy UK Limited, a company organized under the laws of the United Kingdom (“Endeavour Energy UK”), did not, individually or in aggregate, account for more than 10% of the consolidated net income of the Company and its Subsidiaries for the year ended December 31, 2011.

(oo) Neither the Company nor any subsidiary nor any of their affiliates (within the meaning of FINRA’s NASD Conduct Rule 5121(f)(1)) directly or indirectly controls, is controlled by, or is under common control with, or is an associated person (within the meaning of Article I, Section 1(ee) of the By-laws of FINRA) of, any member firm of FINRA.

(pp) No forward-looking statement (within the meaning of Section 27A of the Act and Section 21E of the Exchange Act) contained in the Registration Statement, the Disclosure Package and the Final Prospectus has been made or reaffirmed without a reasonable basis or has been disclosed other than in good faith.

Any certificate signed by any officer of the Company and delivered to the Underwriter or counsel for the Underwriter in connection with the offering of the Shares shall be deemed a representation and warranty by the Company, as to matters covered thereby, to the Underwriter.

2. Purchase and Sale.

(a) Subject to the terms and conditions and in reliance upon the representations and warranties herein set forth, the Company agrees to sell to the Underwriter, and the Underwriter agrees to purchase from the Company, at the purchase price set forth in Schedule I hereto, the number of Firm Shares set forth opposite the Underwriter’s name in Schedule II hereto.

(b) Subject to the terms and conditions and in reliance upon the representations and warranties herein set forth, the Company hereby grants an option to the Underwriter to purchase up to the number of Option Shares set forth in Schedule I hereto at the same purchase price per share as the Underwriter shall pay for the Firm Shares, less an amount per share equal to any dividends or distributions declared by the Company and payable on the Firm Shares but not payable on the Option Shares. Said option may be exercised only to cover over-allotments in the sale of the Firm Shares by the Underwriter. Said option may be exercised in whole or in part at any time on or before the 30th day after the date of the Final Prospectus upon written or telegraphic notice by the Underwriter to the

Company setting forth the number of Option Shares as to which the Underwriter is exercising the option and the settlement date. The number of Option Shares to be purchased by the Underwriter shall be the same percentage of the total number of Option Shares to be purchased by the Underwriter as the Underwriter is purchasing of the Firm Shares, subject to such adjustments as the Underwriter in its absolute discretion shall make to eliminate any fractional shares.

3. Delivery and Payment. Delivery of and payment for the Firm Shares and the Option Shares (if the option provided for in Section 2(b) hereof shall have been exercised on or before the third Business Day immediately preceding the Closing Date) shall be made at the place and on the date and at the time specified in Schedule I hereto or at such time on such later date not more than three Business Days after the foregoing date as the Underwriter shall designate, which date and time may be postponed by agreement between the Underwriter and the Company or as provided in Section 9 hereof (such date and time of delivery and payment for the Shares being herein called the “Closing Date”). Delivery of the Shares shall be made to the Underwriter against payment by the Underwriter of the purchase price thereof to or upon the order of the Company by wire transfer payable in same-day funds to an account specified by the Company. Delivery of the Firm Shares and the Option Shares shall be made through the facilities of The Depository Trust Company via DWAC delivery unless the Underwriter shall otherwise instruct.

If the option provided for in Section 2(b) hereof is exercised after the third (3^rd) Business Day immediately preceding the Closing Date, the Company will deliver the Option Shares (at the expense of the Company) to the Underwriter at the place and on the date specified by the Underwriter (which shall be within three Business Days after exercise of said option), against payment by the Underwriter of the purchase price thereof to or upon the order of the Company by wire transfer payable in same-day funds to an account specified by the Company. If settlement for the Option Shares occurs after the Closing Date, the Company will deliver to the Underwriter on the settlement date for the Option Shares, and the obligation of the Underwriter to purchase the Option Shares shall be conditioned upon receipt of, supplemental opinions, certificates and letters confirming as of such date the opinions, certificates and letters delivered on the Closing Date pursuant to Section 6 hereof.

4. Offering by Underwriter. It is understood that the Underwriter proposes to offer the Shares for sale to the public as set forth in the Final Prospectus.

5. Agreements. The Company agrees with the Underwriter that:

(a) Prior to the termination of the offering of the Shares, the Company will not file any amendment of the Registration Statement or supplement (including the Final Prospectus or any Preliminary Prospectus) to the Base Prospectus or any Rule 462(b) Registration Statement unless the Company has furnished you a copy for your review prior to filing and will not file any such proposed amendment or supplement to which you reasonably object. The Company will cause the Final Prospectus, properly completed, and any supplement thereto to be filed in a form approved by the Underwriter with the Commission pursuant to the applicable paragraph of Rule 424(b) within the time period prescribed and will provide evidence satisfactory to the Underwriter of such

timely filing. The Company will promptly advise the Underwriter (i) when the Final Prospectus, and any supplement thereto, shall have been filed (if required) with the Commission pursuant to Rule 424(b) or when any Rule 462(b) Registration Statement shall have been filed with the Commission, (ii) when, prior to termination of the offering of the Shares, any amendment to the Registration Statement shall have been filed or become effective, (iii) of any request by the Commission or its staff for any amendment of the Registration Statement, or any Rule 462(b) Registration Statement, or for any supplement to the Final Prospectus or for any additional information, (iv) of the issuance by the Commission of any stop order suspending the effectiveness of the Registration Statement or of any notice objecting to its use or the institution or threatening of any proceeding for that purpose and (v) of the receipt by the Company of any notification with respect to the suspension of the qualification of the Shares for sale in any jurisdiction or the institution or threatening of any proceeding for such purpose. The Company will use its best efforts to prevent the issuance of any such stop order or the occurrence of any such suspension or objection to the use of the Registration Statement and, upon such issuance, occurrence or notice of objection, to obtain as soon as possible the withdrawal of such stop order or relief from such occurrence or objection, including, if necessary, by filing an amendment to the Registration Statement or a new registration statement and using its best efforts to have such amendment or new registration statement declared effective as soon as practicable.

(b) If, at any time prior to the filing of the Final Prospectus pursuant to Rule 424(b), any event occurs as a result of which the Disclosure Package would include any untrue statement of a material fact or omit to state any material fact necessary to make the statements therein in the light of the circumstances under which they were made or the circumstances then prevailing not misleading, the Company will (i) notify promptly the Underwriter so that any use of the Disclosure Package may cease until it is amended or supplemented; (ii) amend or supplement the Disclosure Package to correct such untrue statement or omission; and (iii) supply any amendment or supplement to you in such quantities as you may reasonably request.

(c) If, at any time when a prospectus relating to the Shares is required to be delivered under the Act (including in circumstances where such requirement may be satisfied pursuant to Rule 172), any event occurs as a result of which the Final Prospectus as then supplemented would include any untrue statement of a material fact or omit to state any material fact necessary to make the statements therein in the light of the circumstances under which they were made not misleading, or if it shall be necessary to amend the Registration Statement, file a new registration statement or supplement the Final Prospectus to comply with the Act or the Exchange Act or the respective rules thereunder, including in connection with use or delivery of the Final Prospectus, the Company promptly will (i) notify the Underwriter of any such event, (ii) prepare and file with the Commission, subject to the second sentence of paragraph (a) of this Section 5, an amendment or supplement or new registration statement which will correct such statement or omission or effect such compliance, (iii) use its best efforts to have any amendment to the Registration Statement or new registration statement declared effective as soon as practicable in order to avoid any disruption in use of the Final Prospectus and (iv) supply any supplemented Final Prospectus to you in such quantities as you may reasonably request.

(d) As soon as practicable, the Company will make generally available to its security holders and to the Underwriter an earnings statement or statements of the Company and its Subsidiaries which will satisfy the provisions of Section 11(a) of the Act and Rule 158.

(e) The Company will furnish to the Underwriter and counsel for the Underwriter, without charge, copies of the Registration Statement (including exhibits thereto) and to each other Underwriter a copy of the Registration Statement (without exhibits thereto) and, so long as delivery of a prospectus by an Underwriter or dealer may be required by the Act (including in circumstances where such requirement may be satisfied pursuant to Rule 172), as many copies of each Preliminary Prospectus, the Final Prospectus and each Issuer Free Writing Prospectus and any supplement thereto as the Underwriter may reasonably request. The Company will pay the expenses of printing or other production of all documents relating to the offering.

(f) The Company will arrange, if necessary, for the qualification of the Shares for sale under the laws of such jurisdictions as the Underwriter may designate and will maintain such qualifications in effect so long as required for the distribution of the Shares; provided that in no event shall the Company be obligated to qualify to do business in any jurisdiction where it is not now so qualified or to take any action that would subject it to service of process in suits, other than those arising out of the offering or sale of the Shares, in any jurisdiction where it is not now so subject.

(g) The Company agrees that, unless it has or shall have obtained the prior written consent of the Underwriter, and the Underwriter agrees with the Company that, unless it has or shall have obtained, as the case may be, the prior written consent of the Company, it has not made and will not make any offer relating to the Shares that would constitute an Issuer Free Writing Prospectus or that would otherwise constitute a “free writing prospectus” (as defined in Rule 405) required to be filed by the Company with the Commission or retained by the Company under Rule 433; provided that the prior written consent of the parties hereto shall be deemed to have been given in respect of the Free Writing Prospectuses included in Schedule III hereto and any electronic road show. Any such free writing prospectus consented to by the Underwriter or the Company is hereinafter referred to as a “Permitted Free Writing Prospectus.” The Company agrees that (x) it has treated and will treat, as the case may be, each Permitted Free Writing Prospectus as an Issuer Free Writing Prospectus and (y) it has complied and will comply, as the case may be, with the requirements of Rules 164 and 433 applicable to any Permitted Free Writing Prospectus, including in respect of timely filing with the Commission, legending and record keeping.

(h) The Company will not, without the prior written consent of the Underwriter, offer, sell, contract to sell, pledge, or otherwise dispose of, (or enter into any transaction which is designed to, or might reasonably be expected to, result in the disposition (whether by actual disposition or effective economic disposition due to cash

settlement or otherwise) by the Company or any affiliate of the Company or any person in privity with the Company or any affiliate of the Company) directly or indirectly, including the filing (or participation in the filing) of a registration statement with the Commission in respect of, or establish or increase a put equivalent position or liquidate or decrease a call equivalent position within the meaning of Section 16 of the Exchange Act, any other shares of Common Stock or any securities convertible into, or exercisable, or exchangeable for, shares of Common Stock; or publicly announce an intention to effect any such transaction, until the date set forth on Schedule I hereto; provided, however, that the Company may (A) issue and sell Common Stock pursuant to any employee stock option plan, stock ownership plan or dividend reinvestment plan of the Company in effect at the Execution Time, (B) issue Common Stock issuable upon the conversion of securities or the exercise of warrants outstanding at the Execution Time, (C) file a registration statement with the Commission on Form S-8 relating to the offering of securities pursuant to the terms of any employee stock option plan, stock ownership plan or dividend reinvestment plan of the Company in effect at the Execution Time, (D) issue Common Stock to directors in lieu of cash as payment of Board of Director fees, and (E) issue the Shares to be sold hereunder.

(i) The Company will not take, directly or indirectly, any action designed to or that would constitute or that could reasonably be expected to cause or result in, under the Exchange Act or otherwise, stabilization or manipulation of the price of any security of the Company to facilitate the sale or resale of the Shares.

(j) The Company will apply the net proceeds from the sale of the Shares as described in the Final Prospectus under the heading “Use of Proceeds.”

(k) The Company will use its reasonable best efforts to list, subject to notice of issuance, and maintain the listing of the Shares on the NYSE.

(l) The Company agrees to pay the costs and expenses relating to the following matters: (i) the preparation, printing or reproduction and filing with the Commission of the Registration Statement (including financial statements and exhibits thereto), each Preliminary Prospectus, the Final Prospectus and each Issuer Free Writing Prospectus, and each amendment or supplement to any of them; (ii) the printing (or reproduction) and delivery (including postage, air freight charges and charges for counting and packaging) of such copies of the Registration Statement, each Preliminary Prospectus, the Final Prospectus and each Issuer Free Writing Prospectus, and all amendments or supplements to any of them, as may, in each case, be reasonably requested for use in connection with the offering and sale of the Shares; (iii) the preparation, printing, authentication, issuance and delivery of certificates for the Shares, including any stamp or transfer taxes in connection with the original issuance and sale of the Shares; (iv) the printing (or reproduction) and delivery of this Agreement, any blue sky memorandum and all other agreements or documents printed (or reproduced) and delivered in connection with the offering of the Shares; (v) the registration of the Shares under the Exchange Act and the listing of the Shares on the NYSE; (vi) any registration or qualification of the Shares for offer and sale under the securities or blue sky laws of the several states (including filing fees and the reasonable fees and expenses of counsel

for the Underwriter relating to such registration and qualification); (vii) any filings required to be made with the Financial Industry Regulatory Authority, Inc. (including filing fees and the reasonable fees and expenses of counsel for the Underwriter relating to such filings); (viii) the transportation, roadshow and other expenses incurred by or on behalf of Company representatives, including one-half of the roadshow and other expenses of the Underwriter, in connection with presentations to prospective purchasers of the Shares; (ix) the fees and expenses of the Company’s accountants and the fees and expenses of counsel (including local and special counsel) for the Company; (x) one half of the fees, disbursements and expenses of counsel to the Underwriter, which shall be payable from the gross offering proceeds by wire transfer to underwriter’s counsel on the Closing Date; and (xi) all other costs and expenses incident to the performance by the Company of its obligations hereunder.

(m) The Company acknowledges the requirement under listing rule 14.3.4 of the UK Listing Rules to apply for admission to listing of the Shares on the official list of the London Stock Exchange (“UK Admission”) and hereby undertakes and confirms to the Underwriter that it shall as soon as possible and in any event within one year of the Closing Date, at its own expense, make application:

(i) to the Financial Services Authority of the United Kingdom (“FSA”):

(1) for formal approval of a prospectus relating to the offering and sale of the Shares as a prospectus pursuant to the UK Prospectus Rules; and

(2) for the admission of the Shares to the official list of the London Stock Exchange; and

(ii) to the London Stock Exchange plc for the admission of the Shares to trading on its market for listed securities,

and that it shall (i) supply to the FSA and London Stock Exchange plc respectively all documents required to be provided by the Company, (ii) give such undertakings, (iii) execute all such documents, (iv) pay all such fees and (v) generally do or procure to be done all such things as may required in relation to such applications for the purpose of obtaining the approval and grant of the UK Admission.

In this Section 5(m), “UK Listing Rules” means the listing rules made by the FSA pursuant to Financial Services and Markets ▇▇▇ ▇▇▇▇, as revised from time to time and “UK Prospectus Rules” means the rules made for the purposes of the Financial Services and Markets ▇▇▇ ▇▇▇▇ in relation to offers of securities to the public and admission of securities to trading on a regulated market, as revised from time to time.

6. Conditions to the Obligations of the Underwriter. The obligations of the Underwriter to purchase the Firm Shares and the Option Shares, as the case may be, shall be subject to the accuracy of the representations and warranties on the part of the Company contained herein as of the Execution Time, the Closing Date and any subsequent settlement date

(solely with respect to the Option Shares) pursuant to Section 3 hereof (except to the extent such representations and warranties expressly relate to a specific earlier date (in which case such representations and warranties shall be true and correct as of such specified earlier date)), to the accuracy of the statements of the Company made in any certificates pursuant to the provisions hereof, to the performance by the Company of its obligations hereunder and to the following additional conditions:

(a) The Final Prospectus, and any supplement thereto, have been filed in the manner and within the time period required by Rule 424(b); any material required to be filed by the Company pursuant to Rule 433(d) under the Act shall have been filed with the Commission within the applicable time periods prescribed for such filings by Rule 433; and no stop order suspending the effectiveness of the Registration Statement or any notice objecting to its use shall have been issued and no proceedings for that purpose shall have been instituted or threatened.

(b) ▇▇▇▇▇▇ & ▇▇▇▇▇▇ LLP, counsel for the Company, shall have furnished to the Underwriter, at the request of the Company, their written opinions and 10b-5 statement, dated the Closing Date or the Option Closing Date, as the case may be, and addressed to the Underwriter, in form and substance reasonably satisfactory to the Underwriter, to the effect set forth in Exhibit B hereto.

(c) The Underwriter shall have received the opinion of ▇▇▇▇▇▇▇▇ and Wedge, opining as to the law of Nevada, addressed to the Underwriter and dated the Closing Date, to the effect set forth in Exhibit C hereto.

(d) The Underwriter shall have received on and as of the Closing Date or the Option Closing Date, as the case may be, an opinion and 10b-5 statement of Proskauer Rose LLP, counsel for the Underwriter, with respect to such matters as the Underwriter may reasonably request, and such counsel shall have received such documents and information as they may reasonably request to enable them to pass upon such matters.

(e) On or before the execution of this Agreement, the Underwriter shall have received from NSA a letter addressed to the Underwriter in the form and substance reasonably satisfactory to the Underwriter containing statements and information with respect to the oil and gas reserves of the Company and its subsidiaries and of the COP Assets as reported in the Disclosure Package and the Final Prospectus, and, as of the Closing, such letter shall not have been withdrawn by NSA or amended by NSA in any material respect.

(f) The Company shall have furnished to the Underwriter a certificate of the Company, signed by the Chairman of the Board, the President and Chief Executive Officer and the principal financial or accounting officer of the Company, dated the Closing Date, to the effect that the signers of such certificate have carefully examined the Registration Statement, the Disclosure Package, the Final Prospectus and any supplements or amendments thereto, as well as each electronic road show used in connection with the offering of the Shares, and this Agreement and that:

(i) the representations and warranties of the Company in this Agreement are true and correct on and as of the Closing Date with the same effect as if made on the Closing Date (except to the extent such representations and warranties expressly relate to a specific earlier date (in which case such representations and warranties shall be true and correct as of such specified earlier date)) and the Company has complied with all the agreements and satisfied all the conditions on its part to be performed or satisfied at or prior to the Closing Date;

(ii) no stop order suspending the effectiveness of the Registration Statement or any notice objecting to its use has been issued and no proceedings for that purpose have been instituted or, to the Company’s knowledge, threatened; and

(iii) since the date of the most recent financial statements included in the Disclosure Package and the Final Prospectus (exclusive of any supplement thereto), there has been no Material Adverse Effect, except as set forth in or contemplated in the Disclosure Package and the Final Prospectus (exclusive of any supplement thereto).

(g) At the time of the execution of this Agreement, KPMG LLP shall have furnished to the Underwriter a letter, dated the date hereof and addressed to the Underwriter, in form and substance reasonably satisfactory to the Underwriter, containing statements and information of the type customarily included in accountants’ “comfort letters” to underwriters with respect to the financial statements and certain financial information contained or incorporated by reference in the Registration Statement, the Disclosure Package and the Final Prospectus; provided, that the letter delivered shall use a “cut-off” date no more than three (3) business days prior to the date hereof.

(h) (1) At the time of the execution of this Agreement, Ernst & Young LLP shall have furnished to the Underwriter a letter, dated the date hereof and addressed to the Underwriter, in form and substance reasonably satisfactory to the Underwriter, containing statements and information of the type customarily included in accountants’ “comfort letters” to underwriters with respect to the financial statements and certain financial information contained or incorporated by reference in the Registration Statement, the Disclosure Package and the Final Prospectus; provided, that the letter delivered shall use a “cut-off” date no more than three (3) business days prior to the date hereof; and (2) on the Closing Date and any Option Closing Date (if such date is other than the Closing Date), the Underwriter shall have received a bring-down comfort letter from Ernst & Young LLP addressed to the Underwriter and dated the Closing Date and any Option Closing Date (if such date is other than the Closing Date) confirming, as of the date of the bring-down letter (or, with respect to matters involving changes or developments since the respective dates as of which specified financial information is given in the Disclosure Package and the Final Prospectus, as the case may be, as of a date not more than three (3) business days prior to the date of the bring-down letter), the conclusions and findings of such firm, of the type ordinarily included in accountants’ “comfort letters” to underwriters, with respect to the financial information and other matters covered by its letter delivered to the Underwriter concurrently with the execution of this Agreement pursuant to this paragraph (h)(1) of this Section 6.

(i) Subsequent to the Execution Time or, if earlier, the dates as of which information is given in the Registration Statement (exclusive of any amendment thereof) and the Final Prospectus (exclusive of any amendment or supplement thereto), there shall not have been (i) any change or decrease specified in the letter or letters referred to in paragraph (e) of this Section 6, (ii) any Material Adverse Effect or (iii) any action taken or law, statute, rule, regulation or order enacted, adopted or issued, or any issuance of an injunction or order, by any federal, state or foreign governmental or regulatory authority, the effect of which, in any case referred to in clause (i), (ii) or (iii) above, is, in the sole judgment of the Underwriter, so material and adverse as to make it impractical or inadvisable to proceed with the offering or delivery of the Shares as contemplated by the Registration Statement (exclusive of any amendment thereof), the Disclosure Package and the Final Prospectus (exclusive of any amendment or supplement thereto).

(j) Subsequent to the Execution Time, there shall not have been any decrease in the rating of any of the Company’s debt securities by any “nationally recognized statistical rating organization” (as defined for purposes of Rule 3(a)(2) under the Exchange Act) or any notice given of any intended or potential decrease in any such rating or of a possible change in any such rating that does not indicate the direction of the possible change.

(k) The Shares shall have been listed and admitted and authorized for trading on the NYSE, and reasonably satisfactory evidence of such actions shall have been provided to the Underwriter or counsel for the Underwriter.

(l) At the Execution Time, the Company shall have furnished to the Underwriter a letter substantially in the form of Exhibit A hereto from each executive officer and director of the Company set forth on Schedule IV hereto, addressed to the Underwriter, which shall be full force and effect on the Closing Date and any Option Closing Date, as the case may be.

(m) Prior to the Closing Date, the Company shall have furnished to the Underwriter such further information, certificates (both of officers and various secretaries of state evidencing good standing), opinions and documents as the Underwriter may reasonably request.

If any of the conditions specified in this Section 6 shall not have been fulfilled when and as provided in this Agreement, or if any of the opinions and certificates mentioned above or elsewhere in this Agreement shall not be reasonably satisfactory in form and substance to the Underwriter and counsel for the Underwriter, this Agreement and all obligations of the Underwriter hereunder may be canceled at, or at any time prior to, the Closing Date by the Underwriter. Notice of such cancellation shall be given to the Company in writing or by telephone or facsimile confirmed in writing. In connection with the purchase of any Option Shares on any settlement date, references to the “Closing Date” in this Section 6 shall instead refer to such settlement date.

The documents required to be delivered by this Section 6 shall be delivered at the office of Proskauer Rose LLP, counsel for the Underwriter, Eleven Times Square, New York, N.Y. 2012 at 10:00 a.m., EST, on June 18, 2012 on the Closing Date for review by the Underwriter or Proskauer Rose LLP.

7. Reimbursement of Underwriter’s Expenses. If the sale of the Shares provided for herein is not consummated because any condition to the obligations of the Underwriter set forth in Section 6 hereof is not satisfied, because of any termination pursuant to Section 9 hereof or because of any refusal, inability or failure on the part of the Company to perform any agreement herein or comply with any provision hereof other than by reason of a default by the Underwriter, the Company will reimburse the Underwriter on demand for all expenses (including reasonable fees and disbursements of counsel) that shall have been incurred by them in connection with the proposed purchase and sale of the Shares.

8. Indemnification and Contribution.

(a) The Company agrees to indemnify and hold harmless the Underwriter, the directors, officers, employees and agents of the Underwriter and each person who controls the Underwriter within the meaning of either the Act or the Exchange Act against any and all losses, claims, damages or liabilities, joint or several, to which they or any of them may become subject under the Act, the Exchange Act or other Federal or state statutory law or regulation, at common law or otherwise, insofar as such losses, claims, damages or liabilities (or actions in respect thereof) arise out of or are based upon any untrue statement or alleged untrue statement of a material fact contained in the registration statement for the registration of the Shares as originally filed or in any amendment thereof, or in the Base Prospectus, any Preliminary Prospectus or any other preliminary prospectus supplement relating to the Shares, the Final Prospectus or any Issuer Free Writing Prospectus, or in any amendment thereof or supplement thereto, or arise out of or are based upon the omission or alleged omission to state therein a material fact required to be stated therein or necessary to make the statements therein not misleading, and agrees to reimburse each such indemnified party, as incurred, for any legal or other expenses reasonably incurred by them in connection with investigating or defending any such loss, claim, damage, liability or action; provided, however, that the Company will not be liable in any such case to the extent that any such loss, claim, damage or liability arises out of or is based upon any such untrue statement or alleged untrue statement or omission or alleged omission made therein in reliance upon and in conformity with written information furnished to the Company by or on behalf of the Underwriter specifically for inclusion therein. This indemnity agreement will be in addition to any liability which the Company may otherwise have.

(b) The Underwriter agrees to indemnify and hold harmless the Company, each of its directors, each of its officers who signs the Registration Statement, and each person who controls the Company within the meaning of either the Act or the Exchange Act, to the same extent as the foregoing indemnity from the Company to the Underwriter, but only with reference to written information furnished to the Company by the Underwriter specifically for inclusion in the documents referred to in the foregoing indemnity. This indemnity agreement will be in addition to any liability which the

Underwriter may otherwise have. The Company acknowledges that (i) the statements set forth the [last] paragraph on the front cover page concerning the terms of the offering of the Shares; and (ii) the statements concerning the Underwriter contained in the [first] paragraph, the first sentence of the second paragraph concerning the securities being subject to prior sale, in the [fourth] paragraph concerning the terms of the offering of the Shares, concerning stabilization by the Underwriter in the [tenth] paragraph and in the [twelfth] paragraph concerning the offering of the Shares, in each case under the heading “Underwriting” constitute the only information furnished in writing by the Underwriter for inclusion in any Preliminary Prospectus, the Final Prospectus or any Issuer Free Writing Prospectus.

(c) Promptly after receipt by an indemnified party under this Section 8 of notice of the commencement of any action, such indemnified party will, if a claim in respect thereof is to be made against the indemnifying party under this Section 8, notify the indemnifying party in writing of the commencement thereof; but the failure so to notify the indemnifying party (i) will not relieve it from liability under paragraph (a) or (b) above unless and to the extent it did not otherwise learn of such action and such failure results in the forfeiture by the indemnifying party of substantial rights and defenses and (ii) will not, in any event, relieve the indemnifying party from any obligations to any indemnified party other than the indemnification obligation provided in paragraph (a) or (b) above. The indemnifying party shall be entitled to appoint counsel of the indemnifying party’s choice at the indemnifying party’s expense to represent the indemnified party in any action for which indemnification is sought (in which case the indemnifying party shall not thereafter be responsible for the fees and expenses of any separate counsel retained by the indemnified party or parties except as set forth below); provided, however, that such counsel shall be satisfactory to the indemnified party. Notwithstanding the indemnifying party’s election to appoint counsel to represent the indemnified party in an action, the indemnified party shall have the right to employ separate counsel (including local counsel), and the indemnifying party shall bear the reasonable fees, costs and expenses of such separate counsel if (i) the use of counsel chosen by the indemnifying party to represent the indemnified party would present such counsel with a conflict of interest, (ii) the actual or potential defendants in, or targets of, any such action include both the indemnified party and the indemnifying party and the indemnified party shall have reasonably concluded that there may be legal defenses available to it and/or other indemnified parties which are different from or additional to those available to the indemnifying party, (iii) the indemnifying party shall not have employed counsel satisfactory to the indemnified party to represent the indemnified party within a reasonable time after notice of the institution of such action or (iv) the indemnifying party shall authorize the indemnified party in writing to employ separate counsel at the expense of the indemnifying party. An indemnifying party will not, without the prior written consent of the indemnified parties, settle or compromise or consent to the entry of any judgment with respect to any pending or threatened claim, action, suit or proceeding in respect of which indemnification or contribution may be sought hereunder (whether or not the indemnified parties are actual or potential parties to such claim or action) unless such settlement, compromise or consent includes an unconditional release of each indemnified party from all liability arising out of such claim, action, suit or proceeding.

In the event that the indemnity provided in paragraph (a), (b) or (c) of this Section 8 is unavailable to or insufficient to hold harmless an indemnified party for any reason, the Company and the Underwriter agrees to contribute to the aggregate losses, claims, damages and liabilities (including legal or other expenses reasonably incurred in connection with investigating or defending the same) (collectively “Losses”) to which the Company and the Underwriter may be subject in such proportion as is appropriate to reflect the relative benefits received by the Company on the one hand and by the Underwriter on the other from the offering of the Shares; provided, however, that in no case shall the Underwriter be responsible for any amount in excess of the underwriting discount or commission applicable to the Shares purchased by the Underwriter hereunder. If the allocation provided by the immediately preceding sentence is unavailable for any reason, the Company and the Underwriter severally shall contribute in such proportion as is appropriate to reflect not only such relative benefits but also the relative fault of the Company on the one hand and of the Underwriter on the other in connection with the statements or omissions which resulted in such Losses as well as any other relevant equitable considerations. Benefits received by the Company shall be deemed to be equal to the total net proceeds from the offering (before deducting expenses) received by it, and benefits received by the Underwriter shall be deemed to be equal to the total underwriting discounts and commissions, in each case as set forth on the cover page of the Final Prospectus. Relative fault shall be determined by reference to, among other things, whether any untrue or any alleged untrue statement of a material fact or the omission or alleged omission to state a material fact relates to information provided by the Company on the one hand or the Underwriter on the other, the intent of the parties and their relative knowledge, access to information and opportunity to correct or prevent such untrue statement or omission. The Company and the Underwriter agree that it would not be just and equitable if contribution were determined by pro rata allocation or any other method of allocation which does not take account of the equitable considerations referred to above. Notwithstanding the provisions of this paragraph (d), no person guilty of fraudulent misrepresentation (within the meaning of Section 11(f) of the Act) shall be entitled to contribution from any person who was not guilty of such fraudulent misrepresentation. For purposes of this Section 8, each person who controls an Underwriter within the meaning of either the Act or the Exchange Act and each director, officer, employee and agent of the Underwriter shall have the same rights to contribution as the Underwriter, and each person who controls the Company within the meaning of either the Act or the Exchange Act, each officer of the Company who shall have signed the Registration Statement and each director of the Company shall have the same rights to contribution as the Company, subject in each case to the applicable terms and conditions of this paragraph (d).

9. Termination. This Agreement shall be subject to termination in the absolute discretion of the Underwriter, by notice given to the Company prior to delivery of and payment for the Shares, if at any time prior to such delivery and payment (i) trading in the Company’s Common Stock shall have been suspended by the Commission or the NYSE or trading in securities generally on the NYSE shall have been suspended or limited or minimum prices shall have been established on either of such exchanges, (ii) a banking moratorium shall have been declared either by Federal or New York State authorities or (iii) there shall have occurred any outbreak or escalation of hostilities, declaration by the United States of a national emergency or war, or other calamity or crisis the effect of which on financial markets is such as to make it, in the sole judgment of the Underwriter, impractical or inadvisable to proceed with the offering or delivery of the Shares as contemplated by any Preliminary Prospectus or the Final Prospectus (exclusive of any amendment or supplement thereto).

10. Representations and Indemnities to Survive. The respective agreements, representations, warranties, indemnities and other statements of the Company or its officers and of the Underwriter set forth in or made pursuant to this Agreement will remain in full force and effect, regardless of any investigation made by or on behalf of the Underwriter or the Company or any of the officers, directors, employees, agents or controlling persons referred to in Section 8 hereof, and will survive delivery of and payment for the Shares. The provisions of Sections 7 and 8 hereof shall survive the termination or cancellation of this Agreement.

11. Notices. All communications hereunder will be in writing and effective only on receipt, and, if sent to the Underwriter, will be mailed, delivered or telefaxed to Global Hunter Securities, LLC, ▇▇▇ ▇▇▇▇▇▇▇ ▇▇▇▇▇▇, ▇▇▇▇▇ ▇▇▇▇, ▇▇▇ ▇▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇, (fax: (▇▇▇) ▇▇▇-▇▇▇▇); Attention: ▇▇▇▇ ▇▇▇▇▇▇▇▇, General Counsel; or, if sent to the Company, will be mailed, delivered or telefaxed to J. ▇▇▇▇▇▇▇ ▇▇▇▇▇▇▇ (fax no.: (▇▇▇) ▇▇▇-▇▇▇▇) and confirmed to it at ▇▇▇▇ ▇▇▇▇▇▇ ▇▇▇▇▇▇, ▇▇▇▇▇ ▇▇▇▇, ▇▇▇▇▇▇▇, ▇▇▇▇▇ ▇▇▇▇▇, Attention: Chief Financial Officer.

12. Successors. This Agreement will inure to the benefit of and be binding upon the parties hereto and their respective successors and the officers, directors, employees, agents and controlling persons referred to in Section 8 hereof, and no other person will have any right or obligation hereunder.

13. No Fiduciary Duty. The Company hereby acknowledges that (a) the purchase and sale of the Shares pursuant to this Agreement is an arm’s-length commercial transaction between the Company, on the one hand, and the Underwriter and any affiliate through which it may be acting, on the other, (b) the Underwriter is acting as principal and not as an agent or fiduciary of the Company and (c) the Company’s engagement of the Underwriter in connection with the offering and the process leading up to the offering is as independent contractors and not in any other capacity. Furthermore, the Company agrees that it is solely responsible for making its own judgments in connection with the offering (irrespective of whether the Underwriter has advised or is currently advising the Company on related or other matters). The Company agrees that it will not claim that the Underwriter have rendered advisory services of any nature or respect, or owe an agency, fiduciary or similar duty to the Company, in connection with such transaction or the process leading thereto.

14. Integration. This Agreement supersedes all prior agreements and understandings (whether written or oral) between the Company and the Underwriter, or any of them, with respect to the subject matter hereof.

15. Applicable Law. This Agreement and any claim, controversy or dispute arising under or related to this Agreement shall be governed by and construed in accordance with the laws of the State of New York.

16. Waiver of Jury Trial. The Company hereby irrevocably waives, to the fullest extent permitted by applicable law, any and all right to trial by jury in any legal proceeding arising out of or relating to this Agreement or the transactions contemplated hereby.

17. Counterparts. This Agreement may be signed in one or more counterparts, each of which shall constitute an original and all of which together shall constitute one and the same agreement.

18. Headings. The section headings used herein are for convenience only and shall not affect the construction hereof.

19. Research Analyst Independence. The Company acknowledges that the Underwriter’s research analysts and research departments are required to be independent from its investment banking division and are subject to certain regulations and internal policies, and that the Underwriter’s research analysts may hold views and make statements or investment recommendations and/or publish research reports with respect to the Company and/or the offering of the Shares that differ from the views of their investment banking division. The Company hereby waives and releases, to the fullest extent permitted by law, any claims that the Company may have against the Underwriter with respect to any conflict of interest that may arise from the fact that the views expressed by its independent research analysts and research departments may be different from or inconsistent with the views or advice communicated to the Company by the Underwriter’s investment banking division. The Company acknowledges that the Underwriter is a full service securities firm and as such from time to time, subject to applicable securities laws, rules and regulations, may effect transactions for its own account or the account of its customers and hold long or short positions in debt or equity securities of the Company; provided, however, that nothing in this Section 19 shall relieve the Underwriter of any responsibility or liability it may otherwise bear in connection with activities in violation of applicable securities laws, rules or regulations.

20. Definitions. The terms that follow, when used in this Agreement, shall have the meanings indicated.

“Act” shall mean the Securities Act of 1933, as amended, and the rules and regulations of the Commission promulgated thereunder.

“Base Prospectus” shall mean the base prospectus referred to in paragraph 1(a) above contained in the Registration Statement at the Execution Time.

“Business Day” shall mean any day other than a Saturday, a Sunday or a legal holiday or a day on which banking institutions or trust companies are authorized or obligated by law to close in New York City or Houston, Texas.

“Commission” shall mean the Securities and Exchange Commission.

“Disclosure Package” shall mean (i) the Base Prospectus, (ii) the Preliminary Prospectus used most recently prior to the Execution Time, (iii) the Issuer Free Writing Prospectuses, if any, identified in Schedule III hereto, and (iv) any other Free Writing Prospectus that the parties hereto shall hereafter expressly agree in writing to treat as part of the Disclosure Package.

“Effective Date” shall mean each date and time that the Registration Statement, any post-effective amendment or amendments thereto and any Rule 462(b) Registration Statement became or becomes effective.

“Exchange Act” shall mean the Securities Exchange Act of 1934, as amended, and the rules and regulations of the Commission promulgated thereunder.

“Execution Time” shall mean 8:45 a.m., New York City time, on June 13, 2012.

“Final Prospectus” shall mean the prospectus supplement relating to the Shares that was first filed pursuant to Rule 424(b) after the Execution Time, together with the Base Prospectus.

“Free Writing Prospectus” shall mean a free writing prospectus, as defined in Rule 405.

“Knowledge”, shall mean the knowledge of the executive officers and directors of the Company after reasonable inquiry.

“Issuer Free Writing Prospectus” shall mean an issuer free writing prospectus, as defined in Rule 433.

“Preliminary Prospectus” shall mean any preliminary prospectus supplement to the Base Prospectus referred to in paragraph 1(a) above which is used prior to the filing of the Final Prospectus, together with the Base Prospectus.

“Registration Statement” shall mean the registration statement referred to in paragraph 1(a) above, including exhibits and financial statements and any prospectus supplement relating to the Shares that is filed with the Commission pursuant to Rule 424(b) and deemed part of such registration statement pursuant to Rule 430B, as amended on each Effective Date and, in the event any post-effective amendment thereto or any Rule 462(b) Registration Statement becomes effective prior to the Closing Date, shall also mean such registration statement as so amended or such Rule 462(b) Registration Statement, as the case may be.

“Rule 158,” “Rule 163,” “Rule 164,” “Rule 172,” “Rule 405,” “Rule 415,” “Rule 424,” “Rule 430B,” “Rule 433” and “Rule 462” refer to such rules under the Act.

“Rule 462(b) Registration Statement” shall mean a registration statement and any amendments thereto filed pursuant to Rule 462(b) relating to the offering covered by the registration statement referred to in Section 1(a) hereof.

“Subsidiaries” shall mean the subsidiaries of the Company set forth on Exhibit 21.1 to the Company’s Annual Report on Form 10-K for the year ended December 31, 2011.

If the foregoing is in accordance with your understanding of our agreement, please sign and return to us the enclosed duplicate hereof, whereupon this letter and your acceptance shall represent a binding agreement between the Company and the Underwriter.


Very truly yours,

ENDEAVOUR INTERNATIONAL CORPORATION

By:		/s/ J. ▇▇▇▇▇▇▇ ▇▇▇▇▇▇▇
Name: J. ▇▇▇▇▇▇▇ ▇▇▇▇▇▇▇ Title: Executive VP and Chief Financial Officer

Signature Page to Underwriting Agreement

The foregoing Agreement is

hereby confirmed and accepted

as of the date specified in

Schedule I hereto.


Global Hunter Securities, LLC

By:		/s/ ▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇▇▇▇▇
		Name: ▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇▇▇▇▇ Title: President

Signature Page to Underwriting Agreement

SCHEDULE I

Underwriting Agreement dated June 13, 2012

Registration Statement No. 333-163781

Underwriter: Global Hunter Securities, LLC

Title, Purchase Price and Description of Securities:

Title: Common Stock, par value $0.001 per share

Number of Firm Shares to be sold by the Company: 7,500,000

Number of Option Shares to be sold by the Company: 1,125,000

Price per Share to Public: $7.50

Price per Share to the Underwriter: $7.125

Other provisions: None

Closing Date, Time and Location: Proskauer Rose LLP, Eleven Times Square, ▇▇▇ ▇▇▇▇, ▇▇ ▇▇▇▇▇, at 10:00 EST on June 18, 2012

Type of Offering: Non-Delayed

Date referred to in Section 5(h) after which the Company may offer or sell securities issued by the Company without the consent of the Underwriter: September 13, 2012

SCHEDULE I

SCHEDULE II


Underwriter	Number of Firm Shares to be Purchased
Global Hunter Securities, LLC		7,500,000

Total		7,500,000

SCHEDULE II

SCHEDULE III

Schedule of Free Writing Prospectuses included in the Disclosure Package

None.

SCHEDULE III

SCHEDULE IV

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J. ▇▇▇▇▇▇▇ ▇▇▇▇▇▇▇

▇▇▇▇▇▇ ▇. ▇▇▇▇▇▇▇▇

▇▇▇▇ ▇. ▇▇▇▇▇

▇▇▇▇ ▇. ▇▇▇▇▇▇▇▇ III

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▇▇▇▇▇▇▇ ▇▇▇ ▇▇▇▇▇▇▇▇

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SCHEDULE IV

EXHIBIT A

FORM OF LOCK-UP AGREEMENT

GLOBAL HUNTER SECURITIES, LLC

▇▇▇ ▇▇▇▇▇▇▇ ▇▇▇▇▇▇, ▇▇▇▇▇ ▇▇▇▇

▇▇▇ ▇▇▇▇▇▇▇, ▇▇▇▇▇▇▇▇▇ ▇▇▇▇▇

Attention: General Counsel

Re: Endeavour International Corporation — Public Offering of Common Stock

Ladies and Gentlemen:

In order to induce you, as the underwriter (the “Underwriter”), to enter into that certain Underwriting Agreement with Endeavour International Corporation, a Nevada corporation (the “Company”), with respect to the public offering of the Common Stock, par value per share of $0.001, of the Company, the undersigned hereby agrees that for a period of ninety (90) days (the “Lock-up Period”) following the date of the final prospectus filed by the Company with the Securities and Exchange Commission in connection with such public offering, the undersigned will not, without the prior written consent of the Underwriter, directly or indirectly, (i) offer, sell, assign, transfer, pledge, contract to sell, or otherwise dispose of, any shares of Common Stock or securities convertible into or exercisable or exchangeable for Common Stock (including, without limitation, shares of Common Stock or any such securities which may be deemed to be beneficially owned by the undersigned in accordance with the rules and regulations promulgated under the Securities Act of 1933, as the same may be amended or supplemented from time to time (such shares or securities, the “Beneficially Owned Shares”)), (ii) enter into any swap, hedge or other agreement or arrangement that transfers in whole or in part, the economic risk of ownership of any Beneficially Owned Shares, Common Stock or securities convertible into or exercisable or exchangeable for Common Stock, or (iii) engage in any short selling of any Beneficially Owned Shares, Common Stock or securities convertible into or exercisable or exchangeable for Common Stock.

Anything contained herein to the contrary notwithstanding, any person to who shares of Common Stock, securities convertible into or exercisable or exchangeable for Common Stock or Beneficially Owned Shares are transferred from the undersigned shall be bound by the terms of this Agreement.

In addition, the undersigned hereby waives, from the date hereof until the expiration of the ninetieth (90^th) day following the date of the Company’s final prospectus, any and all rights, if any, to request or demand registration pursuant to the Securities Act of 1933, as amended, of any shares of Common Stock or securities convertible into or exercisable or exchangeable for Common Stock that are registered in the name of the undersigned or that are Beneficially Owned Shares. In order to enable the aforesaid covenants to be enforced, the undersigned hereby consents to the placing of

legends and/or stop transfer orders with the transfer agent of the Common Stock with respect to any shares of Common Stock, securities convertible into or exercisable or exchangeable for Common Stock or Beneficially Owned Shares.

This Letter Agreement and any claim, controversy or dispute arising under or related to this Letter Agreement shall be governed by and construed in accordance with the laws of the State of New York, without regard to the conflict of laws principles thereof.


				Very truly yours,

				[NAME OF DIRECTOR/OFFICER]

				By:
						Name:
						Title:

Exhibit B

Opinions of ▇▇▇▇▇▇ & ▇▇▇▇▇▇

(i) the Registration Statement has become effective under the Act; any required filing of the Base Prospectus, any Preliminary Prospectus and the Final Prospectus, and any supplements thereto, pursuant to Rule 424(b) has been made in the manner and within the time period required by Rule 424(b); to the knowledge of such counsel, no stop order suspending the effectiveness of the Registration Statement or any notice objecting to its use has been issued, no proceedings for that purpose have been instituted or threatened, and the Registration Statement and the Final Prospectus (other than the financial statements and other financial and statistical information and reserve information contained therein, as to which such counsel need express no opinion) appeared on their face to have complied as to form in all material respects with the applicable requirements of the Act and the Exchange Act and the respective rules thereunder;

(ii) each of Endeavour Operating and Endeavour Energy UK is validly existing in good standing under the laws of the jurisdiction in which it is chartered or organized, with full corporate or limited liability company, as applicable, power and authority to own or lease its properties, as the case may be, and conduct its business as described in the Disclosure Package and the Final Prospectus, and each of the Company, Endeavour Operating and Endeavour Energy UK is in good standing under the laws of the jurisdictions set forth on Schedule I;

(iii) to the knowledge of such counsel, (A) there is no pending or threatened action, suit or proceeding by or before any court or governmental agency, authority or body to which the Company or any of its Subsidiaries is a party or to which any of their respective properties are subject, of a character required to be disclosed in the Registration Statement which is not disclosed in the Disclosure Package and the Final Prospectus as required, and (B) there is no contract or other document of a character required to be described in the Registration Statement, the Disclosure Package or Final Prospectus, or to be filed as an exhibit thereto, which is not described or filed as required; and the section of the Disclosure Package and the Final Prospectus entitled “Certain United States Federal Income Tax Consequences for Non-U.S. Holders of Our Common Stock,” insofar as it purports to constitute a summary of United States federal tax law and regulations or legal conclusions with respect thereto, constitutes an accurate summary of the matters described therein in all material respects, subject to the assumptions and qualifications set forth therein; and the statements contained or incorporated by reference in the Disclosure Package and the Final Prospectus under the caption, “Business—Environmental Matters and Regulation” and “Business—Regulations,” insofar as they refer to statements of law or legal conclusions, accurately describe, in all material respects, the statutes and regulations addressed thereby.;

(iv) the Company is not and, after giving effect to the offering and sale of the Securities and the application of the proceeds therefrom as described in the Disclosure Package and the Final Prospectus, will not be required to register as, an “investment company” as defined in the Investment Company Act of 1940, as amended;

(v) no consent, approval, authorization, filing with or order of any court or governmental agency or body is required in connection with the transactions contemplated herein, except such as have been obtained under the Act and such as may be required under the blue sky laws of any jurisdiction in connection with the purchase and distribution of the Securities by the Underwriters in the manner contemplated in this Agreement, the Disclosure Package and the Final Prospectus and such other approvals (specified in such opinion) as have been obtained;

(vi) the execution, delivery and performance by the Company of the Underwriting Agreement, the issuance and sale of the Securities being delivered on the Closing Date and the consummation of the transactions contemplated by the Underwriting Agreement do not conflict with, or result in a breach of, or violation of any of the terms or provisions of, or constitute a default under (A) or result in the creation or imposition of any lien, charge or encumbrance upon any property or assets of the Company or any of its subsidiaries pursuant to, any indenture, contract, lease, mortgage, deed of trust, note agreement, loan agreement or other agreement, obligation, condition, covenant or instrument filed or incorporated by reference as an exhibit to the Registration Statement (such documents collectively, the “Applicable Contracts”), (B) any federal or Texas state law, regulation or rule, the Delaware General Corporation Law, or, to our knowledge and without having investigated governmental records or court dockets, any decree, judgment or order applicable to the Company or its Subsidiaries or (C) the organizational documents of Endeavour Operating or Endeavour Energy UK, except, in the case of clauses (A) and (B) above, for any such conflict, breach, violation, default, lien, charge or encumbrance that would not, individually or in the aggregate, have a Material Adverse Effect or with respect to which consents have been obtained. With respect to clause (B) above, such counsel need express no opinion as to the application of any state securities or Blue Sky laws or federal or state antifraud laws, rules or regulations.

(vii) to such counsel’s knowledge, no holders of securities of the Company have rights to the registration of such securities under the Registration Statement.

In addition, such counsel shall state that they have participated in conferences with officers and other representatives of the Company, the independent public accountants of the Company, the independent reserve engineers, the Representative and counsel for the Underwriters, at which the contents of the Registration Statement, the Disclosure Package and the Final Prospectus and related matters were discussed, and although such counsel has not independently verified, is not passing upon, and is not assuming any responsibility for the accuracy, completeness or fairness of the statements contained in, the Registration Statement, the Disclosure Package and the Final Prospectus (except as specifically described in the opinions in paragraph (iv) of the foregoing opinion), based on the foregoing no facts have come to the attention of such counsel that lead such counsel to believe that:

(1) the Registration Statement, as of the latest Effective Date, contained an untrue statement of a material fact or omitted to state a material fact required to be stated therein or necessary to make the statements therein not misleading,

(2) the Disclosure Package, together with the price to public, the number of Underwritten Securities and the number of Option Securities to be included on the cover page of the Final Prospectus, as of the Execution Time, included an untrue statement of a material fact or omitted to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading, or

(3) the Final Prospectus, as of its date and on the Closing Date, included or includes an untrue statement of a material fact or omitted or omits to state a material fact necessary in order to make the statements therein, in the light of the circumstances under which they were made, not misleading;

it being understood that such counsel expresses no statement or belief with respect to (i) the financial statements and related schedules, including the notes thereto and independent registered public accountants’ reports thereon, included or incorporated by reference in the Registration Statement, the Disclosure Package or the Final Prospectus, (ii) any other oil and natural gas reserve and future net revenue information, financial or accounting information or statistical information derived from financial information included or incorporated by reference in or omitted from the Registration Statement, the Disclosure Package or the Final Prospectus, (iii) representations and warranties and other statements of fact included in the exhibits to the Registration Statement or any documents incorporated by reference and (iv) the Form T-1 included as an exhibit to the Registration Statement.

In rendering such opinion, such counsel may rely (A) as to matters involving the application of laws of any jurisdiction other than the States of Delaware or Texas, the laws of the United Kingdom and the Federal laws of the United States, to the extent they

deem proper and specified in such opinion, upon the opinion of other counsel of good standing whom they believe to be reliable and who are satisfactory to counsel for the Underwriters and (B) as to matters of fact, to the extent they deem proper, on certificates of responsible officers of the Company and public officials. References to the Final Prospectus in this paragraph (b) shall also include any supplements thereto at the Closing Date. In the case of opinion points (ii) and (vi)(C), in each case solely with respect to Endeavour Energy UK, such counsel may limit its opinions to the laws of the United Kingdom. With respect to each other opinion, such counsel may limit its opinions to the laws of the States of Delaware and Texas and the Federal laws of the United States.

Exhibit C

Opinion of ▇▇▇▇▇▇▇▇ and Wedge – Nevada Counsel

(i) the Company’s authorized equity capitalization is as set forth in the Disclosure Package and the Final Prospectus; the capital stock of the Company conforms to the description thereof contained in the Disclosure Package and the Final Prospectus; the Securities have been duly and validly authorized, and, when issued and delivered to and paid for by the Underwriters pursuant to this Agreement, will be fully paid and nonassessable; the holders of outstanding shares of Common Stock of the Company are not entitled to preemptive or other rights to subscribe for the Securities and, to our knowledge after due inquiry, except as set forth in the Disclosure Package and the Final Prospectus, no options, warrants or other rights to purchase, agreements or other obligations to issue, or rights to convert any obligations into or exchange any securities for, shares of capital stock of or ownership interests in the company are outstanding;

(ii) the Company has been duly incorporated and is validly existing as a corporation in good standing under the laws of the State of Nevada, with the corporate power and authority to own or lease, as the case may be, and to operate its properties and conduct its business as described in the Disclosure Package and the Final Prospectus;

(iii) this Agreement has been duly authorized, executed and delivered by the Company;

(iv) no consent, approval, authorization, filing with or order of any Nevada court or Nevada governmental agency or body is required in connection with the transactions contemplated herein, except such as have been obtained under the Act and such as may be required under the blue sky laws of any jurisdiction in connection with the purchase and distribution of the Securities by the Underwriters in the manner contemplated in this Agreement, the Disclosure Package and the Final Prospectus (as to which ▇▇▇▇▇▇▇▇ and Wedge shall not offer any opinion) and such other approvals as have been obtained;

(v) neither the issuance and sale of the Securities, nor the consummation of any other of the transactions herein contemplated nor the fulfillment of the terms hereof will conflict with, result in a breach or violation of, or imposition of any lien, charge or encumbrance upon any property or assets of the Company pursuant to, (i) the organizational documents of the Company or (ii) any Nevada statute, law, rule, regulation, or to the knowledge of ▇▇▇▇▇▇▇▇ and Wedge, any judgment, order or decree applicable to the Company of any Nevada court, regulatory body, administrative agency, governmental body, arbitrator or other authority having jurisdiction over the Company or any of its properties;

In rendering such opinion, such counsel may rely (A) as to matters involving the application of laws of any jurisdiction other than the States of Nevada and the Federal laws of the United States, to the extent they deem proper and specified in such opinion, upon the opinion of other counsel of good standing whom they believe to be reliable and who are satisfactory to counsel for the Underwriters and (B) as to matters of fact, to the extent they deem proper, on certificates of responsible officers of the Company and public officials. References to the Final Prospectus in this paragraph (b) shall also include any supplements thereto at the Closing Date. Additionally, the opinions expressed by such counsel may be limited to the laws of the State of Nevada.

7,500,000 Firm Shares of Common Stock Par value $0.001 per share 1,125,000 Option Shares of Common Stock ENDEAVOUR INTERNATIONAL CORPORATION Underwriting Agreement

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