EXHIBIT 99.1

                   CERTIFICATION PURSUANT TO 18 U.S.C. (S)1350

       (ADOPTED PURSUANT TO SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002)

In connection with this Amendment No. 1 to the quarterly report of Dynegy Inc.
(the "Company") on Form 10-Q/A for the period ended June 30, 2002 as filed with
the Securities and Exchange Commission on the date hereof (the "Report"), I,
Bruce A. Williamson, President and Chief Executive Officer of the Company,
hereby certify as of the date hereof, solely for purposes of Title 18, Chapter
63, Section 1350 of the United States Code, that to the best of my knowledge:

(1) the Report fully complies with the requirements of Section 13(a) or 15(d),
as applicable, 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 at
the dates and for the periods indicated.

Date: May 14, 2003

                                           /s/ Bruce A. Williamson
                                           ----------------------------
                                           Bruce A. Williamson
                                           President and Chief Executive Officer