Exhibit 32.1

CERTIFICATION PURSUANT TO

18 U.S.C. SECTION 1350,

AS ADOPTED PURSUANT TO

SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

In connection with the Quarterly Report of ATP Oil & Gas Corporation (the “Company”) on Form 10-Q for the six month period ending June 30, 2008 as filed with the Securities and Exchange Commission on the date hereof (the “Report”), the undersigned hereby certifies, pursuant to 18 U.S.C. Sec. 1350, as adopted pursuant to Sec. 906 of the Sarbanes-Oxley Act of 2002, in his capacity as an officer of the Company, that:

(1) the Report 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 the Report fairly presents, in all material respects, the financial condition and the results of operations of the Company.

Date: August 8, 2008	By:	/s/ T. Paul Bulmahn
		T. Paul Bulmahn Chairman, Chief Executive Officer