-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 NPs7gXh32TMH0Z/THNV3yhYzFzRTMVNosLt09KrJYypPibVYlcEgToo5ombuSiu2
 XrJ2mdMuE2p6eMXTzcDLow==

<SEC-DOCUMENT>0000018230-04-000012.txt : 20040105
<SEC-HEADER>0000018230-04-000012.hdr.sgml : 20040105
<ACCEPTANCE-DATETIME>20040105160718
ACCESSION NUMBER:		0000018230-04-000012
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20031231
FILED AS OF DATE:		20040105

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

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			PARKER JAMES J
		CENTRAL INDEX KEY:			0001173559

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-00768
		FILM NUMBER:		04505041

	BUSINESS ADDRESS:	
		STREET 1:		100 NE ADAMS ST
		CITY:			PEORIA
		STATE:			IL
		ZIP:			61629
		BUSINESS PHONE:		3096754610

	MAIL ADDRESS:	
		STREET 1:		100 NE ADAMS ST
		CITY:			PORIA
		STATE:			IL
		ZIP:			61629
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType><periodOfReport>2003-12-31</periodOfReport>
    <issuer>
        <issuerCik>0000018230</issuerCik>
        <issuerName>CATERPILLAR INC</issuerName>
        <issuerTradingSymbol>CAT</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001173559</rptOwnerCik>
            <rptOwnerName>PARKER JAMES J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>P. O. BOX 610</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MOSSVILLE</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>61552-0610</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>7716</value><footnoteId id="F1"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeHolding></nonDerivativeTable><derivativeTable><derivativeTransaction><securityTitle><value>Phantom Stock Units</value></securityTitle><conversionOrExercisePrice><value>0</value><footnoteId id="F3"/></conversionOrExercisePrice><transactionDate><value>2003-12-31</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>
0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>23</value></transactionShares><transactionPricePerShare><value>0</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>1988-08-08</value><footnoteId id="F2"/></exerciseDate><expirationDate><value>1988-08-08</value><footnoteId id="F2"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common</value></underlyingSecurityTitle><underlyingSecurityShares><value>23</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>0</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeTransaction></derivativeTable><footnotes><footnote id="F1">This amount includes 5908  shares in 40
1K, 888 shares in SEIP and 4 shares in dividend reinvestment.</footnote><footnote id="F2">The reported phantom stock units were acquired under Caterpillar Inc.'s deferred employee investment plan and will be settled upon the reporting person's retirement or other termination of service.</footnote><footnote id="F3">Security converts to common stock on a one-for-one basis.</footnote></footnotes><remarks/><ownerSignature><signatureName>J. J. Parker; L.J. Huxtable, POA</signatureName><signatureDate>2004-01-05</signatureDate></ownerSignature></ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----