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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 GUqpbedZsDN4jwui+wqzeADf4Ee0/bBWXXeW88QDhwbzrboGPN950xAq2/pAeSeG
 i/4aIG96Ki7nx+a5W2Mzkw==

<SEC-DOCUMENT>0001349530-07-000002.txt : 20070814
<SEC-HEADER>0001349530-07-000002.hdr.sgml : 20070814
<ACCEPTANCE-DATETIME>20070814194458
ACCESSION NUMBER:		0001349530-07-000002
CONFORMED SUBMISSION TYPE:	5
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20070630
FILED AS OF DATE:		20070814
DATE AS OF CHANGE:		20070814

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CARPENTER TECHNOLOGY CORP
		CENTRAL INDEX KEY:			0000017843
		STANDARD INDUSTRIAL CLASSIFICATION:	STEEL WORKS, BLAST FURNACES  ROLLING MILLS (COKE OVENS) [3312]
		IRS NUMBER:				230458500
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0630

	BUSINESS ADDRESS:	
		STREET 1:		1047 N PARK ROAD
		CITY:			WYOMISSING
		STATE:			PA
		ZIP:			19610-1339
		BUSINESS PHONE:		6102082000

	MAIL ADDRESS:	
		STREET 1:		1047 N PARK ROAD
		CITY:			WYOMISSING
		STATE:			PA
		ZIP:			19610

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			WADSWORTH JEFFREY
		CENTRAL INDEX KEY:			0001349530

	FILING VALUES:
		FORM TYPE:		5
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-05828
		FILM NUMBER:		071057707

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		6102082000

	MAIL ADDRESS:	
		STREET 1:		C/O CARPENTER TECHNOLOGY CORPORATION
		STREET 2:		PO BOX 14662
		CITY:			READING
		STATE:			PA
		ZIP:			19612
</SEC-HEADER>
<DOCUMENT>
<TYPE>5
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>5</documentType>

    <periodOfReport>2007-06-30</periodOfReport>

    <form3HoldingsReported>0</form3HoldingsReported>

    <form4TransactionsReported>0</form4TransactionsReported>

    <issuer>
        <issuerCik>0000017843</issuerCik>
        <issuerName>CARPENTER TECHNOLOGY CORP</issuerName>
        <issuerTradingSymbol>CRS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001349530</rptOwnerCik>
            <rptOwnerName>WADSWORTH JEFFREY</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>CARPENTER TECHNOLOGY CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>PO BOX 14662</rptOwnerStreet2>
            <rptOwnerCity>READING</rptOwnerCity>
            <rptOwnerState>PA</rptOwnerState>
            <rptOwnerZipCode>19612-4662</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>100</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>867.4</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>867.4</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Converts to common stock on a 1-for-1 basis</footnote>
        <footnote id="F2">Payable upon retirement</footnote>
        <footnote id="F3">Includes dividend equivalents</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>David A. Christiansen/POA</signatureName>
        <signatureDate>2007-08-14</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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