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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,
 ThmdTZOXwlFzqP5wJQXI3t3cr2dfX4qQRSgu9w19cykrIyRpJXdTQgK6tYR6O6XB
 Nz0y6DpZyLNfIp4tv1NuvQ==

<SEC-DOCUMENT>0001270406-03-000002.txt : 20031121
<SEC-HEADER>0001270406-03-000002.hdr.sgml : 20031121
<ACCEPTANCE-DATETIME>20031121175655
ACCESSION NUMBER:		0001270406-03-000002
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20031103
FILED AS OF DATE:		20031121

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			HUNT HERBERT D
		CENTRAL INDEX KEY:			0001270406

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-20725
		FILM NUMBER:		031019122

	MAIL ADDRESS:	
		STREET 1:		C/O SIEBEL SYSTEMS INC
		STREET 2:		2207 BRIDGEPOINTE PARKWAY
		CITY:			SAN MATEO
		STATE:			CA
		ZIP:			94404

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SIEBEL SYSTEMS INC
		CENTRAL INDEX KEY:			0001006835
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-PREPACKAGED SOFTWARE [7372]
		IRS NUMBER:				943187233
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		2207 BRIDGEPOINTE PARKWAY
		CITY:			SAN MATEO
		STATE:			CA
		ZIP:			94404
		BUSINESS PHONE:		6504775000

	MAIL ADDRESS:	
		STREET 1:		2207 BRIDGEPOINTE PARKWAY
		CITY:			SAN MATEO
		STATE:			CA
		ZIP:			94404
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>c0001270406d20031121f3f.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<ownershipDocument><schemaVersion>X0201</schemaVersion>    <documentType>3</documentType><periodOfReport>2003-11-03</periodOfReport><noSecuritiesOwned>0</noSecuritiesOwned><issuer><issuerCik>0001006835</issuerCik><issuerName>SIEBEL SYSTEMS INC</issuerName>        <issuerTradingSymbol>SEBL</issuerTradingSymbol></issuer><reportingOwner><reportingOwnerId><rptOwnerCik>0001270406</rptOwnerCik><rptOwnerName>HUNT HERBERT D</rptOwnerName></reportingOwnerId><reportingOwnerAddress><rptOwnerStreet1>C/O SIEBEL SYSTEMS, INC.</rptOwnerStreet1><rptOwnerStreet2>2207 BRIDGEPOINTE PARKWAY</rptOwnerStreet2><rptOwnerCity>SAN MATEO</rptOwnerCity><rptOwnerState>CA</rptOwnerState><rptOwnerZipCode>94404</rptOwnerZipCode><rptOwnerStateDescription></rptOwnerStateDescription></reportingOwnerAddress><reportingOwnerRelationship><isDirector>0</isDirector><isOfficer>1</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther><officerTitle>Sr. VP, Global Services</officerTitle><otherText></otherText></reportingOwnerRelationshi
p></reportingOwner><nonDerivativeTable></nonDerivativeTable><derivativeTable><derivativeHolding><securityTitle><value>Stock Options (Right to buy)</value></securityTitle><conversionOrExercisePrice><value>8.66</value></conversionOrExercisePrice><exerciseDate><value>2004-05-01</value><footnoteId id="F1"/></exerciseDate><expirationDate><value>2009-04-30</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>150000</value></underlyingSecurityShares></underlyingSecurity><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value></value></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Stock Options (Right to buy)</value></securityTitle><conversionOrExercisePrice><value>12.53</value></conversionOrExercisePrice><exerciseDate><value>2004-11-03</value><footnoteId id="F2"/></exerciseDate><expirationDate><value>2009-11
- -02</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>100000</value></underlyingSecurityShares></underlyingSecurity><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value></value></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Stock Options (Right to buy)</value></securityTitle><conversionOrExercisePrice><value>15.06</value></conversionOrExercisePrice><exerciseDate><value>2002-09-17</value><footnoteId id="F3"/></exerciseDate><expirationDate><value>2011-10-02</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>250000</value></underlyingSecurityShares></underlyingSecurity><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value></value></natu
reOfOwnership></ownershipNature></derivativeHolding></derivativeTable><footnotes><footnote id="F1">The option becomes exercisable as to 20% on May 1, 2004 and as to 5% each quarter thereafter.</footnote><footnote id="F2">The option becomes exercisable as to 20% on November 3, 2004 and as to 5% each quarter thereafter.</footnote><footnote id="F3">The option became exercisable as to 25% on  September 17, 2002 and as to 6.25% each quarter thereafter.</footnote></footnotes><ownerSignature><signatureName>Herbert D. Hunt</signatureName><signatureDate>2003-11-21</signatureDate></ownerSignature></ownershipDocument>

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