ACCOMPANYING CERTIFICATE PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002 Not Filed Pursuant to the Securities Exchange Act of 1934 The undersigned Chief Executive Officer of Harvest Natural Resources, Inc. (the "Company") do hereby certify as follows: Solely for the purpose of meeting the apparent requirements of Section 906 of the Sarbanes-Oxley Act of 2002, and solely to the extent this certification may be applicable to this Annual Report on Form 10-K, the undersigned hereby certify that this Annual Report on Form 10-K fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934 and the information contained in this Annual Report on Form 10-K fairly presents, in all material respects, the financial condition and results of operations of the Company. Dated: March 28, 2003 By: /s/ Peter J. Hill ------------------------------------- Peter J. Hill President and Chief Executive Officer ACCOMPANYING CERTIFICATE PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002 Not Filed Pursuant to the Securities Exchange Act of 1934 The undersigned Chief Financial Officer of Harvest Natural Resources, Inc. (the "Company") do hereby certify as follows: Solely for the purpose of meeting the apparent requirements of Section 906 of the Sarbanes-Oxley Act of 2002, and solely to the extent this certification may be applicable to this Annual Report on Form 10-K, the undersigned hereby certify that this Annual Report on Form 10-K fully complies with the requirements of section 13(a) or 15(d) of the Securities Exchange Act of 1934 and the information contained in this Annual Report on Form 10-K fairly presents, in all material respects, the financial condition and results of operations of the Company. Dated: March 28, 2003 By: /s/ Steven W. Tholen ------------------------------------- Steven W. Tholen Senior Vice President and Chief Financial Officer