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                                                                     EXHIBIT 3.6


                            CERTIFICATE OF AMENDMENT
                                       TO
                          CERTIFICATE OF INCORPORATION
                                       OF
                           HARKEN ENERGY CORPORATION



         Harken Energy Corporation, a corporation organized and exiting under
and by virtue of the General Corporation Law of the State of Delaware (the
"Corporation"), does hereby certify that:

         FIRST:           The name of the Corporation is Harken Energy
                          Corporation.

         SECOND:          The first paragraph of Article Four of the
                          Certificate of Incorporation is hereby amended in its
                          entirety as follows:

                 "The aggregate number of shares which the Corporation shall
                 have the authority to issue is two hundred thirty-five million
                 (235,000,000), of which two hundred twenty- five million
                 (225,000,000) shall be designated as Common Stock of the par
                 value of One Cent ($.01) per share and ten million
                 (10,000,000) shall be designated as Preferred Stock of the par
                 value of One Dollar ($1.00) per share."

         THIRD:           The foregoing amendment to Article Four of the
                          Certificate of Incorporation was duly adopted by the
                          Corporation in accordance with the provisions of
                          Section 242 of the General Corporation Law of the
                          State of Delaware.

         IN WITNESS WHEREOF, Harken Energy Corporation has caused this
Certificate of Amendment to be signed by Gregory S. Porter, its Vice President
- - Legal and Assistant Secretary this 15th day of June, 1998.


                                          HARKEN ENERGY CORPORATION



                                          /s/ Gregory S. Porter               
                                          ------------------------------------
                                          Gregory S. Porter
                                          Vice President - Legal and 
                                          Assistant Secretary