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                                                                     Exhibit 5.1



June 26, 1998





Harken Energy Corporation
5605 N. MacArthur Blvd
Suite 400
Irving, TX  75038

      Re:    Registration Statement on Form S-3

Gentlemen:

      I have acted as counsel to Harken Energy Corporation, a Delaware
corporation (the "Company"), in connection with the registration under the
Securities Act of 1933, as amended (the "Act"), of the offer and sale of an
aggregate of 13,977,446 shares (the "Shares") of common stock, $.01 par value
per share, of the Company ("Common Stock") pursuant to a Registration Statement
on Form S-3 of the Company (the "Registration Statement") to which this opinion
letter is an exhibit.

      In reaching the opinion set forth herein, I have reviewed (a) the
Registration Statement, (b) the Certificate of Incorporation of the Company, as
amended, (c) the Bylaws of the Company, (d) records of proceedings of the Board
of Directors and the stockholders of the Company and (e) except as set forth
below, such other agreements, certificates of public officials and officers of
the Company, records, documents and matters of law that I deemed relevant.

      Based on and subject to the foregoing and subject further to the
assumptions, exceptions and qualifications hereinafter stated, I am of the
opinion that, subject to compliance with federal and state securities laws (as
to which I express no opinion), the Shares have been duly authorized and
validly issued and are fully paid and nonassessable.

      The opinion expressed above is subject in all respects to the following
assumptions, exceptions and qualifications:

      a.     I have assumed that (i) all signatures on all documents examined
             by me are genuine, (ii) all documents submitted to me as originals
             are accurate and complete, (iii) all documents submitted to me as
             copies are true and correct copies of the originals thereof, (iv)
             all information submitted to me is accurate and complete as of the
             date hereof, (v) all persons executing and delivering documents
             reviewed by me were competent to execute and to deliver such
             documents and (vi) that all persons signing, in a representative
             capacity, documents reviewed by me had authority to sign in such
             capacity.

      b.     I have assumed that there are no agreements, indentures,
             mortgages, deeds of trust or instruments that affect the ability
             of the Company to issue the Shares.

      The opinions expressed above are limited to the laws of the State of
Texas, the General Corporation Law of the State of Delaware and the federal
laws of the United States of America.  You should be aware that I am not
admitted to the practice of law in the State of Delaware and my opinion herein
as to the General Corporation Law of the State of Delaware is based solely upon
the unofficial compilation thereof contained in Prentice Hall Information
Services Corporation Statutes.
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Harken Energy Corporation
June 26, 1998
Page 2

      This opinion letter may be filed as an exhibit to the Registration
Statement.  In giving this consent, I do not thereby admit that I come into the
category of persons whose consent is required under Section 7 of the Act or the
rules and regulations of the Securities and Exchange Commission promulgated
thereunder.

      I disclaim any duty to advise you regarding any changes in, or to
otherwise communicate with you with respect to, the matters addressed herein.



                                            Very truly yours,
                                            
                                            
                                            
                                            /s/ Gregory S. Porter
                                            Gregory S. Porter, Esq.