-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 PhhD6pN8Y0NmcFfutLU3/thAMp6Y9ejvnMzSMHJyW0rdDNb6yY1ZtvH+t5WzaFGL
 h4Bjph4nzdXE0HS8rrknkA==

<SEC-DOCUMENT>0000018230-04-000018.txt : 20040106
<SEC-HEADER>0000018230-04-000018.hdr.sgml : 20040106
<ACCEPTANCE-DATETIME>20040106102831
ACCESSION NUMBER:		0000018230-04-000018
CONFORMED SUBMISSION TYPE:	3
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040101
FILED AS OF DATE:		20040106

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			HAEFELI HANS A
		CENTRAL INDEX KEY:			0001273770

	FILING VALUES:
		FORM TYPE:		3
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-00768
		FILM NUMBER:		04508066

	MAIL ADDRESS:	
		STREET 1:		100 NE ADAMS STREET
		CITY:			PEORIA
		STATE:			IL
		ZIP:			61629

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CATERPILLAR INC
		CENTRAL INDEX KEY:			0000018230
		STANDARD INDUSTRIAL CLASSIFICATION:	CONSTRUCTION MACHINERY & EQUIP [3531]
		IRS NUMBER:				370602744
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		100 NE ADAMS ST
		CITY:			PEORIA
		STATE:			IL
		ZIP:			61629
		BUSINESS PHONE:		3096751000

	MAIL ADDRESS:	
		STREET 1:		100 NE ADAMS ST
		CITY:			PEORIA
		STATE:			IL
		ZIP:			61629

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	CATERPILLAR TRACTOR CO
		DATE OF NAME CHANGE:	19860623
</SEC-HEADER>
<DOCUMENT>
<TYPE>3
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>3</documentType><periodOfReport>2004-01-01</periodOfReport>
    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0000018230</issuerCik>
        <issuerName>CATERPILLAR INC</issuerName>
        <issuerTradingSymbol>CAT</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001273770</rptOwnerCik>
            <rptOwnerName>HAEFELI HANS A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>FRANK PERKINS WAY</rptOwnerStreet1>
            <rptOwnerStreet2>EASTFIELD</rptOwnerStreet2>
            <rptOwnerCity>PETERBOROUGH, U.K.</rptOwnerCity>
            <rptOwnerState></rptOwnerState>
            <rptOwnerZipCode>PE1 5NA</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>0</isDirector><isOfficer>1</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther><officerTitle>Vice President</officerTitle></reportingOwnerRelationship></reportingOwner><nonDerivativeTable><nonDerivativeHolding><securityTitle><value>Common</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>4922</value><footnoteId id="F3"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeHolding></nonDerivativeTable><derivativeTable><derivativeHolding><securityTitle><value>Option (NQ)</value><footnoteId id="F2"/></securityTitle><conversionOrExercisePrice><value>55.6875</value></conversionOrExercisePrice><exerciseDate><value>1998-06-09</value><footnoteId id="F1"/></exerciseDate><expirationDate><value>2008-06-09</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>C
ommon</value></underlyingSecurityTitle><underlyingSecurityShares><value>6000</value></underlyingSecurityShares></underlyingSecurity><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Option (NQ)</value><footnoteId id="F2"/></securityTitle><conversionOrExercisePrice><value>62.3438</value></conversionOrExercisePrice><exerciseDate><value>1999-06-08</value><footnoteId id="F1"/></exerciseDate><expirationDate><value>2009-06-08</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common</value></underlyingSecurityTitle><underlyingSecurityShares><value>6228</value></underlyingSecurityShares></underlyingSecurity><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Option (NQ)<
/value><footnoteId id="F2"/></securityTitle><conversionOrExercisePrice><value>62.3438</value></conversionOrExercisePrice><exerciseDate><value>1999-06-08</value><footnoteId id="F1"/></exerciseDate><expirationDate><value>2009-06-08</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common</value></underlyingSecurityTitle><underlyingSecurityShares><value>772</value></underlyingSecurityShares></underlyingSecurity><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Option (NQ)</value><footnoteId id="F2"/></securityTitle><conversionOrExercisePrice><value>38.4063</value></conversionOrExercisePrice><exerciseDate><value>2000-06-12</value><footnoteId id="F1"/></exerciseDate><expirationDate><value>2010-06-12</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common</value></underlyingSecurityTitle><underlyingSe
curityShares><value>3000</value></underlyingSecurityShares></underlyingSecurity><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Option (NQ)</value><footnoteId id="F2"/></securityTitle><conversionOrExercisePrice><value>53.53</value></conversionOrExercisePrice><exerciseDate><value>2001-06-12</value><footnoteId id="F1"/></exerciseDate><expirationDate><value>2011-06-12</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common</value></underlyingSecurityTitle><underlyingSecurityShares><value>8000</value></underlyingSecurityShares></underlyingSecurity><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Option (NQ)</value><footnoteId id="F2"/></securityTitle><conversio
nOrExercisePrice><value>50.715</value></conversionOrExercisePrice><exerciseDate><value>2002-06-11</value><footnoteId id="F1"/></exerciseDate><expirationDate><value>2012-06-11</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common</value></underlyingSecurityTitle><underlyingSecurityShares><value>8500</value></underlyingSecurityShares></underlyingSecurity><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Option (NQ)</value><footnoteId id="F2"/></securityTitle><conversionOrExercisePrice><value>54.285</value></conversionOrExercisePrice><exerciseDate><value>2003-06-10</value><footnoteId id="F1"/></exerciseDate><expirationDate><value>2013-06-10</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common</value></underlyingSecurityTitle><underlyingSecurityShares><value>7860</value></underlyingSecuritySha
res></underlyingSecurity><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding></derivativeTable><footnotes><footnote id="F1">Exercisable in thirds - 1/3 after 1 yr.; 1/3 after 2 yrs.; 1/3 after 3 yrs.</footnote><footnote id="F2">Stock Option (right to buy) granted under company's 1996 Stock Option Plan.</footnote><footnote id="F3">This amount includes 1948 shares in EIP and 75 shares in dividend reinvestment.</footnote></footnotes><remarks/><ownerSignature><signatureName>Hans. A. Haefeli; L.J. Huxtable, POA</signatureName><signatureDate>2004-01-06</signatureDate></ownerSignature></ownershipDocument>

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</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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