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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,
 GaGjxWytun7QPwTWtkt40T87wlnafw6J5wXkMN/tvWWOs0uC+3KR+ieVzViCF+Os
 nxATcMU1/hnfuXeMB4z6/g==

<SEC-DOCUMENT>0001123292-08-000383.txt : 20080516
<SEC-HEADER>0001123292-08-000383.hdr.sgml : 20080516
<ACCEPTANCE-DATETIME>20080516172810
ACCESSION NUMBER:		0001123292-08-000383
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20080515
FILED AS OF DATE:		20080516
DATE AS OF CHANGE:		20080516

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CAPITALSOURCE INC
		CENTRAL INDEX KEY:			0001241199
		STANDARD INDUSTRIAL CLASSIFICATION:	REAL ESTATE INVESTMENT TRUSTS [6798]
		IRS NUMBER:				352206895
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	MAIL ADDRESS:	
		STREET 1:		4445 WILLARD AVE
		STREET 2:		12TH FL
		CITY:			CHEVY CHASE
		STATE:			MD
		ZIP:			20815

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SZWAJKOWSKI MICHAEL C
		CENTRAL INDEX KEY:			0001256326

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-31753
		FILM NUMBER:		08843373

	BUSINESS ADDRESS:	
		STREET 1:		C/O CAPITAL SOURCE INC
		STREET 2:		4445 WILLARD AVENUE 12TH FLOOR
		CITY:			CHEVY CHASE
		STATE:			MD
		ZIP:			20815
		BUSINESS PHONE:		3018412700
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-05-15</periodOfReport>

    <issuer>
        <issuerCik>0001241199</issuerCik>
        <issuerName>CAPITALSOURCE INC</issuerName>
        <issuerTradingSymbol>CSE</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001256326</rptOwnerCik>
            <rptOwnerName>SZWAJKOWSKI MICHAEL C</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O CAPITALSOURCE INC.</rptOwnerStreet1>
            <rptOwnerStreet2>4445 WILLARD AVENUE, 12TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>CHEVY CHASE</rptOwnerCity>
            <rptOwnerState>MD</rptOwnerState>
            <rptOwnerZipCode>20815</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Pres. Structured Fin. Bus.</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-05-15</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>40000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>365208</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes></footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Joseph Turitz, Attorney-in-Fact</signatureName>
        <signatureDate>2008-05-16</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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