-----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,
 RuPuQFzS3p3yjB+3cGuX941SH2n16D/VmO1PVGsZTEYX8tF4c+YKPrkvopxJWjpx
 sGKNrP9qdtzDx0kzzaXaPg==

<SEC-DOCUMENT>0000277948-03-000129.txt : 20031212
<SEC-HEADER>0000277948-03-000129.hdr.sgml : 20031212
<ACCEPTANCE-DATETIME>20031212154314
ACCESSION NUMBER:		0000277948-03-000129
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20031210
FILED AS OF DATE:		20031212

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CSX CORP
		CENTRAL INDEX KEY:			0000277948
		STANDARD INDUSTRIAL CLASSIFICATION:	RAILROADS, LINE-HAUL OPERATING [4011]
		IRS NUMBER:				621051971
		STATE OF INCORPORATION:			VA
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		500 WATER STREET
		STREET 2:		15TH FLOOR
		CITY:			JACKSONVILLE
		STATE:			FL
		ZIP:			32202
		BUSINESS PHONE:		9043593200

	MAIL ADDRESS:	
		STREET 1:		301 WEST BAY STREET
		STREET 2:		21ST FLOOR
		CITY:			JACKSONVILLE
		STATE:			FL
		ZIP:			32202

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			ROYAL FRANK S
		CENTRAL INDEX KEY:			0001004548
		STANDARD INDUSTRIAL CLASSIFICATION:	ELECTRIC SERVICES [4911]
		STATE OF INCORPORATION:			VA
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-08022
		FILM NUMBER:		031051934

	BUSINESS ADDRESS:	
		STREET 1:		1122 N 25TH ST
		STREET 2:		STE A
		CITY:			RICHMOND
		STATE:			VA
		ZIP:			23223
		BUSINESS PHONE:		8047755700

	MAIL ADDRESS:	
		STREET 1:		1122 N 25TH ST
		STREET 2:		STE A
		CITY:			RICHOMOND
		STATE:			VA
		ZIP:			23223
</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>2003-12-10</periodOfReport>
    <issuer>
        <issuerCik>0000277948</issuerCik>
        <issuerName>CSX CORP</issuerName>
        <issuerTradingSymbol>CSX</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001004548</rptOwnerCik>
            <rptOwnerName>ROYAL FRANK S</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1122 NORTH 25TH STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>RICHMOND</rptOwnerCity>
            <rptOwnerState>VA</rptOwnerState>
            <rptOwnerZipCode>23223</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>0</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther></reportingOwnerRelationship></reportingOwner><nonDerivativeTable><nonDerivativeTransaction><securityTitle><value>Common stock</value></securityTitle><transactionDate><value>2003-12-10</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>2000</value></transactionShares><transactionPricePerShare><footnoteId id="F2"/></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>18105.1695</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>By trustee</value><footnoteId i
d="F1"/></natureOfOwnership></ownershipNature></nonDerivativeTransaction><nonDerivativeHolding><securityTitle><value>Common stock</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>1000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeHolding></nonDerivativeTable><footnotes><footnote id="F1">By Trustee, CSX Stock Plan for Directors</footnote><footnote id="F2">Stock award pursuant to CSX Corporation Stock Plan for Directors.</footnote></footnotes><remarks/><ownerSignature><signatureName>Frank S. Royal by Rachel E. Geiersbach, Attorney in Fact</signatureName><signatureDate>2003-12-12</signatureDate></ownerSignature></ownershipDocument>

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