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


         In connection with the Quarterly Report of Chesapeake Energy
Corporation (the "Company") on Form 10-Q for the period ended September 30, 2002
as filed with the Securities and Exchange Commission on the date hereof (the
"Report"), I, Aubrey K. McClendon, Chairman and Chief Executive Officer of the
Company, certify, pursuant to 18 U.S.C Section 1350, as adopted pursuant to
Section 906 of the Sarbanes-Oxley Act of 2002, that to the best of my knowledge:

         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 results of
                  operations of the Company.

                                       /s/ AUBREY K. MCCLENDON
                                       -----------------------------------------
                                       Aubrey K. McClendon
                                       Chairman and Chief Executive Officer

Date: November 7, 2002