EXHIBIT 99.1

                            CERTIFICATION PURSUANT TO
                             18 U.S.C. SECTION 1350,
                             AS ADOPTED PURSUANT TO

                  SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002


The undersigned officers of ATP Oil & Gas Corporation (the "Company"), do hereby
certify in accordance with 18 U.S.C. Section 1350, as adopted pursuant to 906 of
the Sarbanes-Oxley Act of 2002, that the foregoing Quarterly Report on Form 10-Q
of the Company for the quarter ended June 30, 2002:

     1)   fully complies with the requirements of section 13 (a) or 15 (d) of
          the Securities Exchange Act of 1934; and

     2)   the information contained in such Quarterly Report on Form 10-Q for
          the quarter ended June 30, 2002, fairly represents, in all material
          respects, the financial condition and the results of operations of the
          Company.



Date:   August 13, 2002        By:      /s/ T. Paul Bulmahn
                                        ----------------------------------------
                                        T. Paul Bulmahn
                                        Chairman, Chief Executive Officer
                                        and President

Date:   August 13, 2002        By:      /s/ Albert L. Reese, Jr.
                                        ----------------------------------------
                                        Albert L. Reese, Jr.
                                        Senior Vice President and Chief
                                        Financial Officer