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 Calpine Corporation (the
"Company") on Form 10-Q for the period ending June 30, 2003, as filed with the
Securities and Exchange Commission on the date hereof (the "Report"), each of
the undersigned does hereby 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 his knowledge, based upon a review of the Report:

         (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 operation of the
Company.

/s/ Peter Cartwright                               /s/ Robert D. Kelly
- --------------------                               -------------------
Peter Cartwright                                   Robert D. Kelly
Chairman, President and                            Executive Vice President and
Chief Executive Officer                            Chief Financial Officer
Calpine Corporation                                Calpine Corporation

Dated: August 14, 2003

A signed original of this written statement required by Section 906 has been
provided to Calpine Corporation and will be retained by Calpine Corporation and
furnished to the Securities and Exchange Commission or its staff upon request.