As filed with the Securities and Exchange Commission on May 13, 2004
                                                Registration No. 333-___________
================================================================================


                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549
                                  ------------

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933
                                  ------------

                               CALPINE CORPORATION
             (Exact Name of Registrant as Specified in Its Charter)

            Delaware                                      77-0212977
  (State or Other Jurisdiction                 (IRS Employer Identification No.)
of Incorporation or Organization)

         50 West San Fernando Street, San Jose, California       95113
               (Address of principal executive offices)        (Zip Code)
                                  ------------

                   CALPINE CORPORATION RETIREMENT SAVINGS PLAN
                            (Full title of the plan)
                                  ------------

                                  Ann B. Curtis
         Executive Vice President, Vice Chairman and Corporate Secretary
                               Calpine Corporation
             50 West San Fernando Street, San Jose, California 95113
                                 (408) 995-5115
            (Name, Address, Including Zip Code, and Telephone Number,
                   Including Area Code, of Agent For Service)
                                  ------------

                         CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>
                                                    Proposed Maximum   Proposed Maximum
Title of Each Class of Securities   Amount to be     Offering Price        Aggregate          Amount of
to be Registered(1)                 Registered(2)     per Share(3)     Offering Price(3)   Registration Fee
---------------------------------   -------------   ---------------   ------------------   ----------------
<S>                                  <C>                 <C>              <C>                  <C>
                                     10,000,000
Common Stock, $.001 par value(4)..     shares            $3.54            $35,400,000          $4,485.18
---------------
<FN>
(1)  Includes certain preferred stock purchase rights (the "Rights")  associated
     with shares of the Common Stock issued pursuant to the Amended and Restated
     Rights Agreement, dated as of September 19, 2001, (the "Rights Agreement"),
     between the Registrant and Equiserve Trust Company, N.A., as rights agent.
     Until the occurrence of certain events  specified in the Rights  Agreement,
     none of which have occurred, the Rights are not exercisable,  are evidenced
     by the  certificate  representing  the Common Stock and will be transferred
     along with and only with the Common Stock.

(2)  Pursuant to Rule 416(a) under the  Securities  Act of 1933, as amended (the
     "1933 Act"),  this  Registration  Statement shall also cover any additional
     shares of Common Stock which become issuable under the Calpine  Corporation
     Retirement  Savings  Plan by  reason of any stock  dividend,  stock  split,
     recapitalization or other similar transaction  effected without the receipt
     of  consideration  which  results  in an  increase  in  the  number  of the
     outstanding shares of Common Stock of Calpine Corporation.

(3)  Calculated  solely for purposes of this  offering  under Rule 457(h) of the
     1933 Act on the basis of the average of the high and low selling prices per
     share of Common  Stock on May 10, 2004,  as  reported  by The New York Stock
     Exchange.

(4)  Pursuant to Rule 416(c)  under the 1933 Act,  this  Registration  Statement
     also registers an indeterminate  amount of  participation  interests in the
     Calpine Corporation Retirement Savings Plan.
</FN>
</TABLE>


<PAGE>

                                     PART II


               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3. Incorporation of Documents by Reference

     Calpine Corporation  ("Calpine") hereby incorporates by reference into this
Registration  Statement  the  following  documents  previously  filed  with  the
Securities  and  Exchange  Commission  (the "SEC")  pursuant  to the  Securities
Exchange Act of 1934, as amended (the "Exchange Act"):

    o  The Annual Report on Form 10-K of Calpine for the year ended December 31,
       2003, filed with the SEC on March 25, 2004;

    o  The  Quarterly  Report on  Form  10-Q of Calpine for  the  quarter  ended
       March 31, 2004, filed with the SEC on May 10, 2004;

    o  The Current Reports on Form 8-K of Calpine, filed with the SEC on January
       6, 2004,  January 9, 2004, January 9, 2004, January 20, 2004, January 29,
       2004,  February 3, 2004,  February 4, 2004, February 6, 2004 and February
       9, 2004,  February 24, 2004,  February 24, 2004, March 1, 2004, March 10,
       2004,  March  12, 2004,  March 16, 2004,  March 23, 2004, April 19, 2004,
       April 28, 2004 and May 12, 2004;

    o  The  Annual  Report on Form 11-K of the  Calpine  Corporation  Retirement
       Savings Plan for the year ended December 31, 2002,  filed with the SEC on
       December 18, 2003;

    o  The  description  of the shares of Common  Stock  contained  in Calpine's
       Registration Statement on Form 8-A, dated August 20, 1996, filed pursuant
       to  Section  12  of  the  Exchange  Act,  and  any  amendment  or  report
       subsequently filed for the purpose of updating that description; and

    o  The  description  of the preferred  stock  purchase  rights  contained in
       Calpine's  Registration Statement on Form 8-A, filed with the SEC on June
       18, 1997, as amended by Calpine's  Registration  Statement on Form 8-A/A,
       filed with the SEC on June 24, 1997, and Calpine's Registration Statement
       on Form 8-A/A,  filed with the SEC on  September  28,  2001,  pursuant to
       Section 12 of the Exchange  Act, and any  additional  amendment or report
       subsequently filed for the purpose of updating that description.

   All documents filed by Calpine Corporation  pursuant to Section 13(a), 13(c),
14 and 15(d) of the Exchange Act after the date of this  Registration  Statement
and prior to the filing of a  post-effective  amendment  that indicates that all
securities offered hereby have been sold or that deregisters all securities then
remaining  unsold,  shall be deemed to be  incorporated  by reference  into this
Registration  Statement  and to be a part hereof from the date of filing of such
documents.

   Any  statement  contained  in  a  document   incorporated  or  deemed  to  be
incorporated  by reference  herein shall be deemed to be modified or  superseded
for  purposes  of this  Registration  Statement  to the extent  that a statement
contained herein or in any subsequently filed document that also is deemed to be
incorporated by reference herein modifies or supersedes such statement. Any such
statement so modified or superseded  shall not be deemed,  except as so modified
or superseded, to constitute a part of this Registration Statement.

   The consolidated  financial  statements for the year ended December 31, 2003,
incorporated in this Registration Statement by reference to the Annual Report on
Form 10-K of the Registrant have been so incorporated in reliance on the reports
of  PricewaterhouseCoopers  LLP,  independent public  accountants,  given on the
authority of said firms as experts in auditing and accounting.



                                       2
<PAGE>

Item 4. Description of Securities

   Not applicable.

Item 5. Interests of Named Experts and Counsel

   Not applicable.

Item 6. Indemnification of Directors and Officers

   Section 145 of the  General  Corporation  Law of the State of  Delaware  (the
"Delaware  Law")  empowers a Delaware  corporation  to indemnify any persons who
are,  or are  threatened  to be made,  parties  to any  threatened,  pending  or
completed  legal  action,   suit  or  proceedings,   whether  civil,   criminal,
administrative  or  investigative  (other than action by or in the right of such
corporation),  by reason of the fact that such person was an officer or director
of such corporation,  or is or was serving at the request of such corporation as
a director, officer, employee or agent of another corporation or enterprise. The
indemnity may include expenses (including attorneys' fees), judgments, fines and
amounts paid in settlement  actually and  reasonably  incurred by such person in
connection with such action,  suit or proceeding,  provided that such officer or
director acted in good faith and in a manner he reasonably  believed to be in or
not opposed to the corporation's best interests,  and, for criminal proceedings,
had no  reasonable  cause to  believe  his  conduct  was  unlawful.  A  Delaware
corporation may indemnify officers and directors in an action by or in the right
of the corporation under the same conditions,  except that no indemnification is
permitted without judicial approval if the officer or director is adjudged to be
liable to the  corporation in the  performance of his duty.  Where an officer or
director is  successful  on the merits or otherwise in the defense of any action
referred to above, the corporation must indemnify him against the expenses which
such officer or director actually and reasonably incurred.

   In accordance with Delaware Law, the certificate of  incorporation of Calpine
contains a provision to limit the personal liability of the directors of Calpine
for  violations  of  their  fiduciary  duty.  This  provision   eliminates  each
director's  liability to Calpine or its stockholders for monetary damages except
(i) for  any  breach  of the  director's  duty  of  loyalty  to  Calpine  or its
stockholders,  (ii) for acts or  omissions  not in good  faith or which  involve
intentional misconduct or a knowing violation of law, (iii) under Section 174 of
the Delaware Law providing  for  liability of directors for unlawful  payment of
dividends  or  unlawful  stock  purchases  or  redemptions,   or  (iv)  for  any
transaction  from which a director  derived an improper  personal  benefit.  The
effect of this provision is to eliminate the personal liability of directors for
monetary damages for actions involving a breach of their fiduciary duty of care,
including any such actions involving gross negligence.

   Article Ten of Calpine's bylaws provides for  indemnification of the officers
and directors of Calpine to the fullest extent permitted by applicable law.

   Calpine has entered into  indemnification  agreements  with its directors and
officers.  These agreements provide  substantially broader indemnity rights than
those provided under the Delaware Law and Calpine's bylaws. The  indemnification
agreements are not intended to deny or otherwise limit third-party or derivative
suits against Calpine or its directors or officers, but if a director or officer
were entitled to indemnity or contribution under the indemnification  agreement,
the  financial  burden of a  third-party  suit  would be borne by  Calpine,  and
Calpine  would not benefit from  derivative  recoveries  against the director or
officer.  Such  recoveries  would  accrue to the benefit of Calpine but would be
offset  by  Calpine's   obligations   to  the  director  or  officer  under  the
indemnification  agreement.  In addition,  the  directors of Calpine are insured
under officers and directors liability insurance policies.



                                       3
<PAGE>

Item 7. Exemption from Registration Claimed

   Not applicable.

Item 8. Exhibits

   In addition to the  exhibits  listed in Calpine's  Registration  Statement on
Form S-8/A, filed with the SEC on May 5, 2000, the following additional exhibits
are filed herewith or incorporated by reference herein:

   EXHIBIT
    NUMBER                       DESCRIPTION
    ------                       -----------
    *4.1  Amended  and  Restated   Certificate  of   Incorporation   of  Calpine
          Corporation (a)
    *4.2  Certificate of Correction of Calpine Corporation (b)
    *4.3  Certificate  of  Amendment  of Amended  and  Restated  Certificate  of
          Incorporation of Calpine Corporation (c)
    *4.4  Certificate of Designation of Series A  Participating  Preferred Stock
          of Calpine Corporation (b)
    *4.5  Amended Certificate of Designation of Series A Participating Preferred
          Stock of Calpine Corporation (b)
    *4.6  Amended Certificate of Designation of Series A Participating Preferred
          Stock of Calpine Corporation (c)
    *4.7  Certificate  of  Designation  of  Special  Voting  Preferred  Stock of
          Calpine Corporation (d)
    *4.8  Certificate  of Ownership and Merger Merging  Calpine  Natural Gas GP,
          Inc. into Calpine Corporation (e)
    *4.9  Certificate  of  Ownership  and Merger  Merging  Calpine  Natural  Gas
          Company into Calpine Corporation (e)
    *4.10 Amended and Restated By-laws of Calpine Corporation (f)
    *4.11 Amended and Restated Rights Agreement, dated as of September 19, 2001,
          between  Calpine  Corporation  and Equiserve  Trust Company,  N.A., as
          Rights Agent (g)
    +23.1 Consent of PricewaterhouseCoopers LLP, Independent Public Accountants
    +23.2 Consent of PricewaterhouseCoopers LLP, Independent Public Accountants
    +23.3 Consent of Deloitte & Touche LLP, Independent Public Accountants
    +23.4 Consent  of  Gilbert  Laustsen  Jung  Associates,   Ltd.,  independent
          engineer
    +23.5 Consent of Netherland, Sewell & Associates, Inc., independent engineer
    +24.1 Power of Attorney of Officers  and  Directors  of Calpine  Corporation
          (set  forth on the  signature  pages of this  Registration  Statement)
----------

+    Filed herewith.

*    Incorporated by reference.

(a)  Incorporated by reference to Calpine Corporation's  Registration  Statement
     on Form S-3  (Registration No.  333-40652),  filed with the SEC on June 30,
     2000.

(b)  Incorporated  by reference to Calpine  Corporation's  Annual Report on Form
     10-K for the year ended December 31, 2000,  filed with the SEC on March 15,
     2001.



                                       4
<PAGE>

(c)  Incorporated by reference to Calpine Corporation's  Registration  Statement
     on Form S-3  (Registration No.  333-66078),  filed with the SEC on July 27,
     2001.

(d)  Incorporated by reference to Calpine Corporation's Quarterly Report on Form
     10-Q dated March 31, 2001, filed with the SEC on May 15, 2001.

(e)  Incorporated by reference to Calpine Corporation's Quarterly Report on Form
     10-Q dated March 31, 2002, filed with the SEC on May 15, 2002.

(f)  Incorporated  by reference to Calpine  Corporation's  Annual Report on Form
     10-K for the year ended December 31, 2001,  filed with the SEC on March 29,
     2002.

(g)  Incorporated by reference to Calpine Corporation's  Registration  Statement
     on Form 8-A/A  (Registration No. 011-12079) filed with the SEC on September
     28, 2001.

     No  opinion  of  counsel  as to the  legality  of the  Common  Stock  being
registered is included in this Registration  Statement because no original issue
shares will be offered and sold under the Plan.

     The  Corporation   has  obtained  from  the  Internal   Revenue  Service  a
determination  letter  that  the  Plan is  qualified  under  Section  401 of the
Internal Revenue Code of 1986, as amended,  and hereby  undertakes to submit any
amendments  to the Plan to the IRS in a timely  manner  and to make any  changes
required by the IRS to maintain the qualification of the Plan under Section 401.

Item 9. Undertakings

     (1) The undersigned Registrant hereby undertakes to file, during any period
in which  offers or sales are being made,  a  post-effective  amendment  to this
Registration Statement:

          (a) to include  any  prospectus  required  by Section  10(a)(3) of the
     Securities Act of 1933;

          (b) to reflect in the prospectus any facts or events arising after the
     effective  date  of  this  Registration   Statement  (or  the  most  recent
     post-effective amendment thereof) which,  individually or in the aggregate,
     represent  a  fundamental  change  in the  information  set  forth  in this
     Registration Statement; and

          (c) to include any  material  information  with respect to the plan of
     distribution not previously disclosed in this Registration Statement or any
     material change to such information in this Registration Statement;

provided, however, that paragraphs 1(a) and 1(b) do not apply if the information
required to be included in a  post-effective  amendment by those  paragraphs  is
contained in periodic  reports filed or furnished by the Registrant  pursuant to
Section  13 or Section  15(d) of the  Securities  Exchange  Act of 1934 that are
incorporated by reference in this Registration Statement.

     (2) The undersigned  Registrant  hereby undertakes that, for the purpose of
determining any liability under the Securities Act of 1933, each  post-effective
amendment  described  under  paragraph (1),  above,  shall be deemed to be a new
registration  statement  relating to the  securities  offered  therein,  and the
offering of such  securities at that time shall be deemed to be the initial bona
fide offering thereof.



                                       5
<PAGE>

     (3)  The   undersigned   Registrant   hereby   undertakes  to  remove  from
registration by means of a post-effective  amendment any of the securities being
registered which remain unsold at the termination of the offering.

     (4) The  undersigned  Registrant  hereby  undertakes  that, for purposes of
determining  any liability  under the Securities Act of 1933, each filing of the
Registrant's  annual  report  pursuant to Section  13(a) or Section 15(d) of the
Securities  Exchange  Act of 1934  that is  incorporated  by  reference  in this
Registration  Statement  shall  be  deemed  to be a new  registration  statement
relating to the securities offered therein,  and the offering of such securities
at that time shall be deemed to be the initial bona fide offering thereof.

     (5) Insofar as indemnification for liabilities arising under the Securities
Act of 1933 may be permitted to directors,  officers and controlling  persons of
the  Registrant  pursuant  to  the  foregoing  provisions,   or  otherwise,  the
Registrant  has been advised that in the opinion of the  Securities and Exchange
Commission  such  indemnification  is against  public policy as expressed in the
Securities  Act of 1933 and is,  therefore,  unenforceable.  In the event that a
claim for  indemnification  against such liabilities  (other than the payment by
the  Registrant  of  expenses  incurred  or  paid  by  a  director,  officer  or
controlling  person of the Registrant in the  successful  defense of any action,
suit or proceeding) is asserted by such director,  officer or controlling person
in connection with the securities being registered,  the Registrant will, unless
in the  opinion  of its  counsel  the matter  has been  settled  by  controlling
precedent,  submit to a court of appropriate  jurisdiction  the question whether
such  indemnification  by it is  against  public  policy  as  expressed  in  the
Securities  Act 1933 and will be  governed  by the  final  adjudication  of such
issue.



                                       6
<PAGE>

                                   SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, as amended, the
Registrant certifies that it has reasonable grounds to believe that it meets all
of  the  requirements  for  filing  on  Form  S-8,  and  has  duly  caused  this
Registration Statement to be signed on its behalf by the undersigned,  thereunto
duly authorized,  in the City of San Jose, State of California, on this 12th day
of May, 2004.


                                       CALPINE CORPORATION


                                       By: /s/ Ann B. Curtis
                                           ----------------------
                                           Ann B. Curtis
                                           Executive Vice President,
                                           Vice Chairman and Corporate Secretary

                                POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS:

     That the  undersigned  officers  and  directors of Calpine  Corporation,  a
Delaware corporation,  do hereby constitute and appoint Peter Cartwright and Ann
B. Curtis and each of them,  the lawful  attorneys-in-fact  and agents with full
power and authority to do any and all acts and things and to execute any and all
instruments which said attorneys and agents, and any one of them,  determine may
be necessary or advisable or required to enable said  corporation to comply with
the  Securities  Act of  1933,  as  amended,  and any  rules or  regulations  or
requirements  of the Securities and Exchange  Commission in connection with this
Registration  Statement.  Without limiting the generality of the foregoing power
and authority,  the powers  granted  include the power and authority to sign the
names of the  undersigned  officers and  directors in the  capacities  indicated
below  to  this  Registration  Statement,  to  any  and  all  amendments,   both
pre-effective   and   post-effective,   and  supplements  to  this  Registration
Statement,  and to any and all  instruments or documents  filed as part of or in
conjunction  with this  Registration  Statement  or  amendments  or  supplements
thereof,  and each of the undersigned hereby ratifies and confirms that all said
attorneys and agents, or any one of them, shall do or cause to be done by virtue
hereof. This Power of Attorney may be signed in several counterparts.

     IN WITNESS  WHEREOF,  each of the  undersigned  has executed  this Power of
Attorney as of the date indicated.

     Pursuant to the  requirements  of the  Securities  Act of 1933, as amended,
this  Registration  Statement has been signed below by the following  persons in
the capacities and on the dates indicated:

<TABLE>
<CAPTION>
             Signature                                            Title                               Date
             ---------                                            -----                               ----
<S>                                              <C>                                               <C>
          /s/ Peter Cartwright                          Chairman, President, Chief                 May 12, 2004
-------------------------------------------            Executive Officer and Director
            Peter Cartwright                            (Principal Executive Officer)


            /s/ Ann B. Curtis                    Executive Vice President, Vice Chairman,          May 12, 2004
-------------------------------------------          Corporate Secretary and Director
              Ann B. Curtis



                                       7
<PAGE>
<CAPTION>
             Signature                                            Title                               Date
             ---------                                            -----                               ----
<S>                                                   <C>                                          <C>
           /s/ Robert D. Kelly                         Executive Vice President and                May 12, 2004
-------------------------------------------              Chief Financial Officer
             Robert D. Kelly                           (Principal Financial Officer)


        /s/ Charles B. Clark, Jr.                       Senior Vice President and                  May 12, 2004
-------------------------------------------                Corporate Controller
          Charles B. Clark, Jr.                       (Principal Accounting Officer)


           /s/ Kenneth T. Derr                                   Director                          May 12, 2004
-------------------------------------------
             Kenneth T. Derr

          /s/Jeffrey E. Garten                                   Director                          May 12, 2004
-------------------------------------------
            Jeffrey E. Garten

          /s/ Gerald Greenwald                                   Director                          May 12, 2004
-------------------------------------------
            Gerald Greenwald

           /s/ Susan C. Schwab                                   Director                          May 12, 2004
-------------------------------------------
             Susan C. Schwab

         /s/ George J. Stathakis                                 Director                          May 12, 2004
-------------------------------------------
           George J. Stathakis

             /s/ Susan Wang                                      Director                          May 12, 2004
-------------------------------------------
               Susan Wang

           /s/ John O. Wilson                                    Director                          May 12, 2004
-------------------------------------------
             John O. Wilson
</TABLE>



                                       8
<PAGE>

                       SECURITIES AND EXCHANGE COMMISSION

                                WASHINGTON, D.C.


                                    EXHIBITS

                                       TO

                                    FORM S-8

                                      UNDER

                             SECURITIES ACT OF 1933


                               CALPINE CORPORATION



                                       9
<PAGE>

   EXHIBIT
    NUMBER                       DESCRIPTION
    ------                       -----------

    *4.1  Amended  and  Restated   Certificate  of   Incorporation   of  Calpine
          Corporation (a)
    *4.2  Certificate of Correction of Calpine Corporation (b)
    *4.3  Certificate  of  Amendment  of Amended  and  Restated  Certificate  of
          Incorporation of Calpine Corporation (c)
    *4.4  Certificate of Designation of Series A  Participating  Preferred Stock
          of Calpine Corporation (b)
    *4.5  Amended Certificate of Designation of Series A Participating Preferred
          Stock of Calpine Corporation (b)
    *4.6  Amended Certificate of Designation of Series A Participating Preferred
          Stock of Calpine Corporation (c)
    *4.7  Certificate  of  Designation  of  Special  Voting  Preferred  Stock of
          Calpine Corporation (d)
    *4.8  Certificate  of Ownership and Merger Merging  Calpine  Natural Gas GP,
          Inc. into Calpine Corporation (e)
    *4.9  Certificate  of  Ownership  and Merger  Merging  Calpine  Natural  Gas
          Company into Calpine Corporation (e)
    *4.10 Amended and Restated By-laws of Calpine Corporation (f)
    *4.11 Amended and Restated Rights Agreement, dated as of September 19, 2001,
          between  Calpine  Corporation  and Equiserve  Trust Company,  N.A., as
          Rights Agent (g)
    +23.1 Consent of PricewaterhouseCoopers LLP, Independent Public Accountants
    +23.2 Consent of PricewaterhouseCoopers LLP, Independent Public Accountants
    +23.3 Consent of Deloitte & Touche LLP, Independent Public Accountants
    +23.4 Consent  of  Gilbert  Laustsen  Jung  Associates,   Ltd.,  independent
          engineer
    +23.5 Consent of Netherland, Sewell & Associates, Inc., independent engineer
    +24.1 Power of Attorney of Officers  and  Directors  of Calpine  Corporation
          (set  forth on the  signature  pages of this  Registration  Statement)
----------

+     Filed herewith.

*     Incorporated by reference.

(a)  Incorporated by reference to Calpine Corporation's  Registration  Statement
     on Form S-3  (Registration No.  333-40652),  filed with the SEC on June 30,
     2000.

(b)  Incorporated  by reference to Calpine  Corporation's  Annual Report on Form
     10-K for the year ended December 31, 2000,  filed with the SEC on March 15,
     2001.

(c)  Incorporated by reference to Calpine Corporation's  Registration  Statement
     on Form S-3  (Registration No.  333-66078),  filed with the SEC on July 27,
     2001.

(d)  Incorporated by reference to Calpine Corporation's Quarterly Report on Form
     10-Q dated March 31, 2001, filed with the SEC on May 15, 2001.

(e)  Incorporated by reference to Calpine Corporation's Quarterly Report on Form
     10-Q dated March 31, 2002, filed with the SEC on May 15, 2002.

(f)  Incorporated  by reference to Calpine  Corporation's  Annual Report on Form
     10-K for the year ended December 31, 2001,  filed with the SEC on March 29,
     2002.

(g)  Incorporated by reference to Calpine Corporation's  Registration  Statement
     on Form 8-A/A  (Registration No. 011-12079) filed with the SEC on September
     28, 2001.



                                       10
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{"company-data": {"conformed-name": "CALPINE CORP", "cik": "0000916457", "assigned-sic": "4911", "irs-number": "770212977", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-115487", "film-number": "04804397"}, "business-address": {"street1": "50 WEST SAN FERNANDO ST", "city": "SAN JOSE", "state": "CA", "zip": "95113", "phone": "4089955115"}, "mail-address": {"street1": "50 W SAN FERNANDO", "street2": "SUITE 500", "city": "SAN JOSE", "state": "CA", "zip": "95113"}}
As filed with the Securities and Exchange Commission on May 13, 2004
                                                Registration No. 333-___________
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549
                                  ------------

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933
                                  ------------

                               CALPINE CORPORATION
             (Exact Name of Registrant as Specified in Its Charter)

            Delaware                                      77-0212977
  (State or Other Jurisdiction                 (IRS Employer Identification No.)
of Incorporation or Organization)

         50 West San Fernando Street, San Jose, California       95113
               (Address of principal executive offices)        (Zip Code)
                                  ------------

                   CALPINE CORPORATION RETIREMENT SAVINGS PLAN
                            (Full title of the plan)
                                  ------------

                                  Ann B. Curtis
         Executive Vice President, Vice Chairman and Corporate Secretary
                               Calpine Corporation
             50 West San Fernando Street, San Jose, California 95113
                                 (408) 995-5115
            (Name, Address, Including Zip Code, and Telephone Number,
                   Including Area Code, of Agent For Service)
                                  ------------

                         CALCULATION OF REGISTRATION FEE
Proposed Maximum   Proposed Maximum
Title of Each Class of Securities   Amount to be     Offering Price        Aggregate          Amount of
to be Registered(1)                 Registered(2)     per Share(3)     Offering Price(3)   Registration Fee
---------------------------------   -------------   ---------------   ------------------   ----------------
10,000,000
Common Stock, $.001 par value(4)..     shares            $3.54            $35,400,000          $4,485.18
---------------
(1)  Includes certain preferred stock purchase rights (the "Rights")  associated
     with shares of the Common Stock issued pursuant to the Amended and Restated
     Rights Agreement, dated as of September 19, 2001, (the "Rights Agreement"),
     between the Registrant and Equiserve Trust Company, N.A., as rights agent.
     Until the occurrence of certain events  specified in the Rights  Agreement,
     none of which have occurred, the Rights are not exercisable,  are evidenced
     by the  certificate  representing  the Common Stock and will be transferred
     along with and only with the Common Stock.

(2)  Pursuant to Rule 416(a) under the  Securities  Act of 1933, as amended (the
     "1933 Act"),  this  Registration  Statement shall also cover any additional
     shares of Common Stock which become issuable under the Calpine  Corporation
     Retirement  Savings  Plan by  reason of any stock  dividend,  stock  split,
     recapitalization or other similar transaction  effected without the receipt
     of  consideration  which  results  in an  increase  in  the  number  of the
     outstanding shares of Common Stock of Calpine Corporation.

(3)  Calculated  solely for purposes of this  offering  under Rule 457(h) of the
     1933 Act on the basis of the average of the high and low selling prices per
     share of Common  Stock on May 10, 2004,  as  reported  by The New York Stock
     Exchange.

(4)  Pursuant to Rule 416(c)  under the 1933 Act,  this  Registration  Statement
     also registers an indeterminate  amount of  participation  interests in the
     Calpine Corporation Retirement Savings Plan.
PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 3. Incorporation of Documents by Reference

     Calpine Corporation  ("Calpine") hereby incorporates by reference into this
Registration  Statement  the  following  documents  previously  filed  with  the
Securities  and  Exchange  Commission  (the "SEC")  pursuant  to the  Securities
Exchange Act of 1934, as amended (the "Exchange Act"):

    o  The Annual Report on Form 10-K of Calpine for the year ended December 31,
       2003, filed with the SEC on March 25, 2004;

    o  The  Quarterly  Report on  Form  10-Q of Calpine for  the  quarter  ended
       March 31, 2004, filed with the SEC on May 10, 2004;

    o  The Current Reports on Form 8-K of Calpine, filed with the SEC on January
       6, 2004,  January 9, 2004, January 9, 2004, January 20, 2004, January 29,
       2004,  February 3, 2004,  February 4, 2004, February 6, 2004 and February
       9, 2004,  February 24, 2004,  February 24, 2004, March 1, 2004, March 10,
       2004,  March  12, 2004,  March 16, 2004,  March 23, 2004, April 19, 2004,
       April 28, 2004 and May 12, 2004;

    o  The  Annual  Report on Form 11-K of the  Calpine  Corporation  Retirement
       Savings Plan for the year ended December 31, 2002,  filed with the SEC on
       December 18, 2003;

    o  The  description  of the shares of Common  Stock  contained  in Calpine's
       Registration Statement on Form 8-A, dated August 20, 1996, filed pursuant
       to  Section  12  of  the  Exchange  Act,  and  any  amendment  or  report
       subsequently filed for the purpose of updating that description; and

    o  The  description  of the preferred  stock  purchase  rights  contained in
       Calpine's  Registration Statement on Form 8-A, filed with the SEC on June
       18, 1997, as amended by Calpine's  Registration  Statement on Form 8-A/A,
       filed with the SEC on June 24, 1997, and Calpine's Registration Statement
       on Form 8-A/A,  filed with the SEC on  September  28,  2001,  pursuant to
       Section 12 of the Exchange  Act, and any  additional  amendment or report
       subsequently filed for the purpose of updating that description.

   All documents filed by Calpine Corporation  pursuant to Section 13(a), 13(c),
14 and 15(d) of the Exchange Act after the date of this  Registration  Statement
and prior to the filing of a  post-effective  amendment  that indicates that all
securities offered hereby have been sold or that deregisters all securities then
remaining  unsold,  shall be deemed to be  incorporated  by reference  into this
Registration  Statement  and to be a part hereof from the date of filing of such
documents.

   Any  statement  contained  in  a  document   incorporated  or  deemed  to  be
incorporated  by reference  herein shall be deemed to be modified or  superseded
for  purposes  of this  Registration  Statement  to the extent  that a statement
contained herein or in any subsequently filed document that also is deemed to be
incorporated by reference herein modifies or supersedes such statement. Any such
statement so modified or superseded  shall not be deemed,  except as so modified
or superseded, to constitute a part of this Registration Statement.

   The consolidated  financial  statements for the year ended December 31, 2003,
incorporated in this Registration Statement by reference to the Annual Report on
Form 10-K of the Registrant have been so incorporated in reliance on the reports
of  PricewaterhouseCoopers  LLP,  independent public  accountants,  given on the
authority of said firms as experts in auditing and accounting.

                                       2
Item 4. Description of Securities

   Not applicable.

Item 5. Interests of Named Experts and Counsel

   Not applicable.

Item 6. Indemnification of Directors and Officers

   Section 145 of the  General  Corporation  Law of the State of  Delaware  (the
"Delaware  Law")  empowers a Delaware  corporation  to indemnify any persons who
are,  or are  threatened  to be made,  parties  to any  threatened,  pending  or
completed  legal  action,   suit  or  proceedings,   whether  civil,   criminal,
administrative  or  investigative  (other than action by or in the right of such
corporation),  by reason of the fact that such person was an officer or director
of such corporation,  or is or was serving at the request of such corporation as
a director, officer, employee or agent of another corporation or enterprise. The
indemnity may include expenses (including attorneys' fees), judgments, fines and
amounts paid in settlement  actually and  reasonably  incurred by such person in
connection with such action,  suit or proceeding,  provided that such officer or
director acted in good faith and in a manner he reasonably  believed to be in or
not opposed to the corporation's best interests,  and, for criminal proceedings,
had no  reasonable  cause to  believe  his  conduct  was  unlawful.  A  Delaware
corporation may indemnify officers and directors in an action by or in the right
of the corporation under the same conditions,  except that no indemnification is
permitted without judicial approval if the officer or director is adjudged to be
liable to the  corporation in the  performance of his duty.  Where an officer or
director is  successful  on the merits or otherwise in the defense of any action
referred to above, the corporation must indemnify him against the expenses which
such officer or director actually and reasonably incurred.

   In accordance with Delaware Law, the certificate of  incorporation of Calpine
contains a provision to limit the personal liability of the directors of Calpine
for  violations  of  their  fiduciary  duty.  This  provision   eliminates  each
director's  liability to Calpine or its stockholders for monetary damages except
(i) for  any  breach  of the  director's  duty  of  loyalty  to  Calpine  or its
stockholders,  (ii) for acts or  omissions  not in good  faith or which  involve
intentional misconduct or a knowing violation of law, (iii) under Section 174 of
the Delaware Law providing  for  liability of directors for unlawful  payment of
dividends  or  unlawful  stock  purchases  or  redemptions,   or  (iv)  for  any
transaction  from which a director  derived an improper  personal  benefit.  The
effect of this provision is to eliminate the personal liability of directors for
monetary damages for actions involving a breach of their fiduciary duty of care,
including any such actions involving gross negligence.

   Article Ten of Calpine's bylaws provides for  indemnification of the officers
and directors of Calpine to the fullest extent permitted by applicable law.

   Calpine has entered into  indemnification  agreements  with its directors and
officers.  These agreements provide  substantially broader indemnity rights than
those provided under the Delaware Law and Calpine's bylaws. The  indemnification
agreements are not intended to deny or otherwise limit third-party or derivative
suits against Calpine or its directors or officers, but if a director or officer
were entitled to indemnity or contribution under the indemnification  agreement,
the  financial  burden of a  third-party  suit  would be borne by  Calpine,  and
Calpine  would not benefit from  derivative  recoveries  against the director or
officer.  Such  recoveries  would  accrue to the benefit of Calpine but would be
offset  by  Calpine's   obligations   to  the  director  or  officer  under  the
indemnification  agreement.  In addition,  the  directors of Calpine are insured
under officers and directors liability insurance policies.

                                       3
Item 7. Exemption from Registration Claimed

   Not applicable.

Item 8. Exhibits

   In addition to the  exhibits  listed in Calpine's  Registration  Statement on
Form S-8/A, filed with the SEC on May 5, 2000, the following additional exhibits
are filed herewith or incorporated by reference herein:

   EXHIBIT
    NUMBER                       DESCRIPTION
    ------                       -----------
    *4.1  Amended  and  Restated   Certificate  of   Incorporation   of  Calpine
          Corporation (a)
    *4.2  Certificate of Correction of Calpine Corporation (b)
    *4.3  Certificate  of  Amendment  of Amended  and  Restated  Certificate  of
          Incorporation of Calpine Corporation (c)
    *4.4  Certificate of Designation of Series A  Participating  Preferred Stock
          of Calpine Corporation (b)
    *4.5  Amended Certificate of Designation of Series A Participating Preferred
          Stock of Calpine Corporation (b)
    *4.6  Amended Certificate of Designation of Series A Participating Preferred
          Stock of Calpine Corporation (c)
    *4.7  Certificate  of  Designation  of  Special  Voting  Preferred  Stock of
          Calpine Corporation (d)
    *4.8  Certificate  of Ownership and Merger Merging  Calpine  Natural Gas GP,
          Inc. into Calpine Corporation (e)
    *4.9  Certificate  of  Ownership  and Merger  Merging  Calpine  Natural  Gas
          Company into Calpine Corporation (e)
    *4.10 Amended and Restated By-laws of Calpine Corporation (f)
    *4.11 Amended and Restated Rights Agreement, dated as of September 19, 2001,
          between  Calpine  Corporation  and Equiserve  Trust Company,  N.A., as
          Rights Agent (g)
    +23.1 Consent of PricewaterhouseCoopers LLP, Independent Public Accountants
    +23.2 Consent of PricewaterhouseCoopers LLP, Independent Public Accountants
    +23.3 Consent of Deloitte & Touche LLP, Independent Public Accountants
    +23.4 Consent  of  Gilbert  Laustsen  Jung  Associates,   Ltd.,  independent
          engineer
    +23.5 Consent of Netherland, Sewell & Associates, Inc., independent engineer
    +24.1 Power of Attorney of Officers  and  Directors  of Calpine  Corporation
          (set  forth on the  signature  pages of this  Registration  Statement)
----------

+    Filed herewith.

*    Incorporated by reference.

(a)  Incorporated by reference to Calpine Corporation's  Registration  Statement
     on Form S-3  (Registration No.  333-40652),  filed with the SEC on June 30,
     2000.

(b)  Incorporated  by reference to Calpine  Corporation's  Annual Report on Form
     10-K for the year ended December 31, 2000,  filed with the SEC on March 15,
     2001.

                                       4
(c)  Incorporated by reference to Calpine Corporation's  Registration  Statement
     on Form S-3  (Registration No.  333-66078),  filed with the SEC on July 27,
     2001.

(d)  Incorporated by reference to Calpine Corporation's Quarterly Report on Form
     10-Q dated March 31, 2001, filed with the SEC on May 15, 2001.

(e)  Incorporated by reference to Calpine Corporation's Quarterly Report on Form
     10-Q dated March 31, 2002, filed with the SEC on May 15, 2002.

(f)  Incorporated  by reference to Calpine  Corporation's  Annual Report on Form
     10-K for the year ended December 31, 2001,  filed with the SEC on March 29,
     2002.

(g)  Incorporated by reference to Calpine Corporation's  Registration  Statement
     on Form 8-A/A  (Registration No. 011-12079) filed with the SEC on September
     28, 2001.

     No  opinion  of  counsel  as to the  legality  of the  Common  Stock  being
registered is included in this Registration  Statement because no original issue
shares will be offered and sold under the Plan.

     The  Corporation   has  obtained  from  the  Internal   Revenue  Service  a
determination  letter  that  the  Plan is  qualified  under  Section  401 of the
Internal Revenue Code of 1986, as amended,  and hereby  undertakes to submit any
amendments  to the Plan to the IRS in a timely  manner  and to make any  changes
required by the IRS to maintain the qualification of the Plan under Section 401.

Item 9. Undertakings

     (1) The undersigned Registrant hereby undertakes to file, during any period
in which  offers or sales are being made,  a  post-effective  amendment  to this
Registration Statement:

          (a) to include  any  prospectus  required  by Section  10(a)(3) of the
     Securities Act of 1933;

          (b) to reflect in the prospectus any facts or events arising after the
     effective  date  of  this  Registration   Statement  (or  the  most  recent
     post-effective amendment thereof) which,  individually or in the aggregate,
     represent  a  fundamental  change  in the  information  set  forth  in this
     Registration Statement; and

          (c) to include any  material  information  with respect to the plan of
     distribution not previously disclosed in this Registration Statement or any
     material change to such information in this Registration Statement;

provided, however, that paragraphs 1(a) and 1(b) do not apply if the information
required to be included in a  post-effective  amendment by those  paragraphs  is
contained in periodic  reports filed or furnished by the Registrant  pursuant to
Section  13 or Section  15(d) of the  Securities  Exchange  Act of 1934 that are
incorporated by reference in this Registration Statement.

     (2) The undersigned  Registrant  hereby undertakes that, for the purpose of
determining any liability under the Securities Act of 1933, each  post-effective
amendment  described  under  paragraph (1),  above,  shall be deemed to be a new
registration  statement  relating to the  securities  offered  therein,  and the
offering of such  securities at that time shall be deemed to be the initial bona
fide offering thereof.

                                       5
(3)  The   undersigned   Registrant   hereby   undertakes  to  remove  from
registration by means of a post-effective  amendment any of the securities being
registered which remain unsold at the termination of the offering.

     (4) The  undersigned  Registrant  hereby  undertakes  that, for purposes of
determining  any liability  under the Securities Act of 1933, each filing of the
Registrant's  annual  report  pursuant to Section  13(a) or Section 15(d) of the
Securities  Exchange  Act of 1934  that is  incorporated  by  reference  in this
Registration  Statement  shall  be  deemed  to be a new  registration  statement
relating to the securities offered therein,  and the offering of such securities
at that time shall be deemed to be the initial bona fide offering thereof.

     (5) Insofar as indemnification for liabilities arising under the Securities
Act of 1933 may be permitted to directors,  officers and controlling  persons of
the  Registrant  pursuant  to  the  foregoing  provisions,   or  otherwise,  the
Registrant  has been advised that in the opinion of the  Securities and Exchange
Commission  such  indemnification  is against  public policy as expressed in the
Securities  Act of 1933 and is,  therefore,  unenforceable.  In the event that a
claim for  indemnification  against such liabilities  (other than the payment by
the  Registrant  of  expenses  incurred  or  paid  by  a  director,  officer  or
controlling  person of the Registrant in the  successful  defense of any action,
suit or proceeding) is asserted by such director,  officer or controlling person
in connection with the securities being registered,  the Registrant will, unless
in the  opinion  of its  counsel  the matter  has been  settled  by  controlling
precedent,  submit to a court of appropriate  jurisdiction  the question whether
such  indemnification  by it is  against  public  policy  as  expressed  in  the
Securities  Act 1933 and will be  governed  by the  final  adjudication  of such
issue.

                                       6
SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, as amended, the
Registrant certifies that it has reasonable grounds to believe that it meets all
of  the  requirements  for  filing  on  Form  S-8,  and  has  duly  caused  this
Registration Statement to be signed on its behalf by the undersigned,  thereunto
duly authorized,  in the City of San Jose, State of California, on this 12th day
of May, 2004.

                                       CALPINE CORPORATION

                                       By: /s/ Ann B. Curtis
                                           ----------------------
                                           Ann B. Curtis
                                           Executive Vice President,
                                           Vice Chairman and Corporate Secretary

                                POWER OF ATTORNEY

KNOW ALL PERSONS BY THESE PRESENTS:

     That the  undersigned  officers  and  directors of Calpine  Corporation,  a
Delaware corporation,  do hereby constitute and appoint Peter Cartwright and Ann
B. Curtis and each of them,  the lawful  attorneys-in-fact  and agents with full
power and authority to do any and all acts and things and to execute any and all
instruments which said attorneys and agents, and any one of them,  determine may
be necessary or advisable or required to enable said  corporation to comply with
the  Securities  Act of  1933,  as  amended,  and any  rules or  regulations  or
requirements  of the Securities and Exchange  Commission in connection with this
Registration  Statement.  Without limiting the generality of the foregoing power
and authority,  the powers  granted  include the power and authority to sign the
names of the  undersigned  officers and  directors in the  capacities  indicated
below  to  this  Registration  Statement,  to  any  and  all  amendments,   both
pre-effective   and   post-effective,   and  supplements  to  this  Registration
Statement,  and to any and all  instruments or documents  filed as part of or in
conjunction  with this  Registration  Statement  or  amendments  or  supplements
thereof,  and each of the undersigned hereby ratifies and confirms that all said
attorneys and agents, or any one of them, shall do or cause to be done by virtue
hereof. This Power of Attorney may be signed in several counterparts.

     IN WITNESS  WHEREOF,  each of the  undersigned  has executed  this Power of
Attorney as of the date indicated.

     Pursuant to the  requirements  of the  Securities  Act of 1933, as amended,
this  Registration  Statement has been signed below by the following  persons in
the capacities and on the dates indicated:
Signature                                            Title                               Date
             ---------                                            -----                               ----
/s/ Peter Cartwright                          Chairman, President, Chief                 May 12, 2004
-------------------------------------------            Executive Officer and Director
            Peter Cartwright                            (Principal Executive Officer)

            /s/ Ann B. Curtis                    Executive Vice President, Vice Chairman,          May 12, 2004
-------------------------------------------          Corporate Secretary and Director
              Ann B. Curtis

                                       7
Signature                                            Title                               Date
             ---------                                            -----                               ----
/s/ Robert D. Kelly                         Executive Vice President and                May 12, 2004
-------------------------------------------              Chief Financial Officer
             Robert D. Kelly                           (Principal Financial Officer)

        /s/ Charles B. Clark, Jr.                       Senior Vice President and                  May 12, 2004
-------------------------------------------                Corporate Controller
          Charles B. Clark, Jr.                       (Principal Accounting Officer)

           /s/ Kenneth T. Derr                                   Director                          May 12, 2004
-------------------------------------------
             Kenneth T. Derr

          /s/Jeffrey E. Garten                                   Director                          May 12, 2004
-------------------------------------------
            Jeffrey E. Garten

          /s/ Gerald Greenwald                                   Director                          May 12, 2004
-------------------------------------------
            Gerald Greenwald

           /s/ Susan C. Schwab                                   Director                          May 12, 2004
-------------------------------------------
             Susan C. Schwab

         /s/ George J. Stathakis                                 Director                          May 12, 2004
-------------------------------------------
           George J. Stathakis

             /s/ Susan Wang                                      Director                          May 12, 2004
-------------------------------------------
               Susan Wang

           /s/ John O. Wilson                                    Director                          May 12, 2004
-------------------------------------------
             John O. Wilson
8
SECURITIES AND EXCHANGE COMMISSION

                                WASHINGTON, D.C.

                                    EXHIBITS

                                       TO

                                    FORM S-8

                                      UNDER

                             SECURITIES ACT OF 1933

                               CALPINE CORPORATION

                                       9
EXHIBIT
    NUMBER                       DESCRIPTION
    ------                       -----------

    *4.1  Amended  and  Restated   Certificate  of   Incorporation   of  Calpine
          Corporation (a)
    *4.2  Certificate of Correction of Calpine Corporation (b)
    *4.3  Certificate  of  Amendment  of Amended  and  Restated  Certificate  of
          Incorporation of Calpine Corporation (c)
    *4.4  Certificate of Designation of Series A  Participating  Preferred Stock
          of Calpine Corporation (b)
    *4.5  Amended Certificate of Designation of Series A Participating Preferred
          Stock of Calpine Corporation (b)
    *4.6  Amended Certificate of Designation of Series A Participating Preferred
          Stock of Calpine Corporation (c)
    *4.7  Certificate  of  Designation  of  Special  Voting  Preferred  Stock of
          Calpine Corporation (d)
    *4.8  Certificate  of Ownership and Merger Merging  Calpine  Natural Gas GP,
          Inc. into Calpine Corporation (e)
    *4.9  Certificate  of  Ownership  and Merger  Merging  Calpine  Natural  Gas
          Company into Calpine Corporation (e)
    *4.10 Amended and Restated By-laws of Calpine Corporation (f)
    *4.11 Amended and Restated Rights Agreement, dated as of September 19, 2001,
          between  Calpine  Corporation  and Equiserve  Trust Company,  N.A., as
          Rights Agent (g)
    +23.1 Consent of PricewaterhouseCoopers LLP, Independent Public Accountants
    +23.2 Consent of PricewaterhouseCoopers LLP, Independent Public Accountants
    +23.3 Consent of Deloitte & Touche LLP, Independent Public Accountants
    +23.4 Consent  of  Gilbert  Laustsen  Jung  Associates,   Ltd.,  independent
          engineer
    +23.5 Consent of Netherland, Sewell & Associates, Inc., independent engineer
    +24.1 Power of Attorney of Officers  and  Directors  of Calpine  Corporation
          (set  forth on the  signature  pages of this  Registration  Statement)
----------

+     Filed herewith.

*     Incorporated by reference.

(a)  Incorporated by reference to Calpine Corporation's  Registration  Statement
     on Form S-3  (Registration No.  333-40652),  filed with the SEC on June 30,
     2000.

(b)  Incorporated  by reference to Calpine  Corporation's  Annual Report on Form
     10-K for the year ended December 31, 2000,  filed with the SEC on March 15,
     2001.

(c)  Incorporated by reference to Calpine Corporation's  Registration  Statement
     on Form S-3  (Registration No.  333-66078),  filed with the SEC on July 27,
     2001.

(d)  Incorporated by reference to Calpine Corporation's Quarterly Report on Form
     10-Q dated March 31, 2001, filed with the SEC on May 15, 2001.

(e)  Incorporated by reference to Calpine Corporation's Quarterly Report on Form
     10-Q dated March 31, 2002, filed with the SEC on May 15, 2002.

(f)  Incorporated  by reference to Calpine  Corporation's  Annual Report on Form
     10-K for the year ended December 31, 2001,  filed with the SEC on March 29,
     2002.

(g)  Incorporated by reference to Calpine Corporation's  Registration  Statement
     on Form 8-A/A  (Registration No. 011-12079) filed with the SEC on September
     28, 2001.

                                       10