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 March 31, 2006, 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/ ROBERT P. MAY                                  /s/ SCOTT J. DAVIDO
- ----------------------------                       ----------------------------
Robert P. May                                      Scott J. Davido
Chief Executive Officer                            Executive Vice President,
Calpine Corporation                                Chief Financial Officer and
                                                   Chief Restructuring Officer
                                                   Calpine Corporation



Dated: June 30, 2006

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.