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                                                                     EXHIBIT 4.2

                          AMENDMENT TO RIGHTS AGREEMENT

         AMENDMENT TO RIGHTS AGREEMENT (this "Amendment") dated as of the 11th
day of March 2003, between Harken Energy Corporation, a Delaware corporation
(the "Company"), and American Stock Transfer and Trust Company (successor to
Mellon Investor Services LLC, a New Jersey limited liability company (formerly
known as ChaseMellon Shareholder Services L.L.C.)), as Rights Agent (the "Rights
Agent").

                                    RECITALS

         1. The Company and the Rights Agent have previously entered into that
certain Rights Agreement, dated as of April 6, 1998 (the "Agreement").

         2. Section 27 (Supplements and Amendments) of the Agreement provides,
in part, that, as long as the Rights are redeemable, the Agreement may be
supplemented or amended without the approval of any holders of Rights.

         3. The Company desires to amend the Agreement to ensure that no Person
will be deemed to be an Acquiring Person (as defined in the Agreement) as a
result of holding the Company's Series G1 Convertible Preferred Stock or Series
G2 Convertible Preferred Stock or as a result of receiving securities of the
Company in exchange for such series of preferred stock.

                                    AGREEMENT

         Section 1. Definitions. All capitalized terms used but not defined
herein shall have the meanings given to them in the Agreement.

         Section 2. Amended Definition. Pursuant to Section 27 of the Agreement
(Supplements and Amendments), the undersigned wish to amend Section 1(k) of the
Agreement (Certain Definitions -- Exempt Person) by deleting the existing
Section 1(k) in its entirety and replacing it with a new Section 1(k) to read as
follows:

         "(k) "Exempt Person" shall mean (i) the Company or any Subsidiary (as
such term is hereinafter defined) of the Company, in each case including,
without limitation, in its fiduciary capacity, or any employee benefit plan of
the Company or any Subsidiary of the Company, or any entity or trustee holding
Common Stock for or pursuant to the terms of any such plan or for the purpose of
funding any such plan or funding other employee benefits for employees of the
Company or of any Subsidiary of the Company, (ii) any Person who or which is or
becomes the Beneficial Owner of 15% or more of the shares of Common Stock then
outstanding as the result of such Person's Beneficial Ownership of the Company's
5% Convertible Notes due 2003, or acquisition from the Company of the Company's
securities, including, but not limited to securities convertible into Common
Stock, and any shares of Common Stock issued by the Company to such Person upon
conversion, exchange or redemption thereof, in exchange for the Company's 5%
Convertible Notes due 2003 held by such Person or both, unless and until such
Person, while a Beneficial Owner of 15% or more of the shares of Common Stock
then

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outstanding as the result of such Person's acquisition from the Company (A) of
rights to subscribe for and purchase Common Stock pursuant to an offering of
such rights which is described in the Company's registration statement to be
filed with the Securities and Exchange Commission in September 2002 (the "Rights
Offering"), and any shares of Common Stock issued to such Person upon exercise
of such rights and (B) of Common Stock pursuant to the Standby Purchase
Agreement to be entered into between Lyford Investments Enterprises Ltd. and the
outstanding, shall become the Beneficial Owner of additional shares of Common
Stock constituting 1% or more of the then outstanding shares of Common Stock
other than pursuant to such exchange, conversion or redemption, (iii) any Person
who or which is or becomes the Beneficial Owner of 15% or more of the shares of
Common Stock thenCompany (the "Standby Purchase Agreement"), unless and until
such Person, while a Beneficial Owner of 15% or more of the shares of Common
Stock then outstanding, shall become a Beneficial Owner of additional shares of
Common Stock constituting 1% or more of the then outstanding shares of Common
Stock other than pursuant to such Rights Offering or the Standby Purchase
Agreement, and (iv) any Person who or which is or becomes the Beneficial Owner
of 15% or more of the shares of Common Stock then outstanding as the result of
such Person's Beneficial Ownership of the Company's Series G1 Convertible
Preferred Stock or Series G2 Convertible Preferred Stock, or acquisition from
the Company of the Company's securities, including, but not limited to
securities convertible into Common Stock, and any shares of Common Stock issued
by the Company to such Person upon conversion, exchange or redemption thereof,
in exchange for the Company's Series G1 Convertible Preferred Stock or Series G2
Convertible Preferred Stock held by such Person or both, unless and until such
Person, while a Beneficial Owner of 15% or more of the shares of Common Stock
then outstanding, shall become the Beneficial Owner of additional shares of
Common Stock constituting 1% or more of the then outstanding shares of Common
Stock other than pursuant to such exchange, conversion or redemption."

         Section 3. Governing Law. This Amendment shall be deemed to be a
contract made under the laws of the State of Delaware and for all purposes shall
be governed by and construed in accordance with the laws of such State
applicable to contracts made and to be performed entirely within such State.

         Section 4. Counterparts. This Agreement may be executed in any number
of counterparts and each of such counterparts shall for all purposes be deemed
to be an original, and all such counterparts shall together constitute but one
and the same instrument.

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         IN WITNESS WHEREOF, the parties hereto have caused this Amendment to
Rights Agreement to be duly executed as of the day and year first above written.

                                       HARKEN ENERGY CORPORATION


                                       By: /s/  Bruce N. Huff
                                           -------------------------------------
                                           Bruce N. Huff

                                           President and Chief Operating Officer

                                       AMERICAN STOCK TRANSFER AND TRUST
                                       COMPANY, as Rights Agent

                                       By: /s/ Joseph Wolf
                                           -------------------------------------
                                           Name: Joseph  Wolf
                                                --------------------------------
                                           Title: Vice President
                                                 -------------------------------

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