-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 SCxFX17kQpWMnUtb+T1YnB5RajCLcbMIivPe+GdgwnL8rJyrBck/Sv125c8oUXUe
 KNPLYfAFvBthI2EiQAJV0w==

<SEC-DOCUMENT>0000017843-09-000006.txt : 20090731
<SEC-HEADER>0000017843-09-000006.hdr.sgml : 20090731
<ACCEPTANCE-DATETIME>20090731193029
ACCESSION NUMBER:		0000017843-09-000006
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20090729
FILED AS OF DATE:		20090731
DATE AS OF CHANGE:		20090731

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			MCMASTER ROBERT R
		CENTRAL INDEX KEY:			0001258998

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-05828
		FILM NUMBER:		09978553

	MAIL ADDRESS:	
		STREET 1:		907-B EAST MAIN STREET
		CITY:			HUMBLE
		STATE:			TX
		ZIP:			77338-4662

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:		2 MERIDIAN BOULEVARD
		CITY:			WYOMISSING
		STATE:			PA
		ZIP:			19612
		BUSINESS PHONE:		6102082000

	MAIL ADDRESS:	
		STREET 1:		PO BOX 14662
		CITY:			READING
		STATE:			PA
		ZIP:			19612-4662
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2009-07-29</periodOfReport>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001258998</rptOwnerCik>
            <rptOwnerName>MCMASTER ROBERT R</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>CARPENTER TECHNOLOGY CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>PO BOX 14662</rptOwnerStreet2>
            <rptOwnerCity>READING</rptOwnerCity>
            <rptOwnerState>PA</rptOwnerState>
            <rptOwnerZipCode>19612</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Options</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>17.29</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2009-07-29</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2358</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2010-07-29</value>
            </exerciseDate>
            <expirationDate>
                <value>2019-07-29</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2358</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2358</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2009-07-29</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>5206</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>17.29</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>5206</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>8361.2989</value>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The reporting person was granted an option to buy shares of common stock under the Carpenter Technology Corporation Stock-Based Compensation Plan for Non-Employee Directors.</footnote>
        <footnote id="F2">Converts to common stock on a 1-for-1 basis</footnote>
        <footnote id="F3">Payable upon retirement</footnote>
        <footnote id="F4">Includes dividend equivalents</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Oliver C. Mitchell/POA</signatureName>
        <signatureDate>2009-07-31</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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