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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 SmRUk2dtnozka2LybS+jJJO73CXpDpmcWOSVBw0KtcNfr3F6jEH4fLVn/XpugG4N
 Vn5pVxdq4QbOyPGg3nl0Dw==

<SEC-DOCUMENT>0000916457-05-000105.txt : 20051216
<SEC-HEADER>0000916457-05-000105.hdr.sgml : 20051216
<ACCEPTANCE-DATETIME>20051216172258
ACCESSION NUMBER:		0000916457-05-000105
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20051212
FILED AS OF DATE:		20051216
DATE AS OF CHANGE:		20051216

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MAY ROBERT P
		CENTRAL INDEX KEY:			0001267313

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-12079
		FILM NUMBER:		051270566

	MAIL ADDRESS:	
		STREET 1:		135 GULFSTREAM ROAD
		CITY:			PALM BEACH
		STATE:			FL
		ZIP:			33480

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CALPINE CORP
		CENTRAL INDEX KEY:			0000916457
		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTRIC SERVICES [4911]
		IRS NUMBER:				770212977
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		50 WEST SAN FERNANDO ST
		CITY:			SAN JOSE
		STATE:			CA
		ZIP:			95113
		BUSINESS PHONE:		4089955115

	MAIL ADDRESS:	
		STREET 1:		50 W SAN FERNANDO
		STREET 2:		SUITE 500
		CITY:			SAN JOSE
		STATE:			CA
		ZIP:			95113
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>i21605-may_ex.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2005-12-12</periodOfReport>

    <noSecuritiesOwned>1</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000916457</issuerCik>
        <issuerName>CALPINE CORP</issuerName>
        <issuerTradingSymbol>CPNL</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001267313</rptOwnerCik>
            <rptOwnerName>MAY ROBERT P</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>CALPINE CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>50 WEST SAN FERNANDO STREET</rptOwnerStreet2>
            <rptOwnerCity>SAN JOSE</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>95113</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Executive Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <ownerSignature>
        <signatureName>Robert P May</signatureName>
        <signatureDate>2005-12-16</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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