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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 JfjbqFtUoavAUiFWUAfgnA==

<SEC-DOCUMENT>0001227320-07-000002.txt : 20070307
<SEC-HEADER>0001227320-07-000002.hdr.sgml : 20070307
<ACCEPTANCE-DATETIME>20070307163829
ACCESSION NUMBER:		0001227320-07-000002
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20070305
FILED AS OF DATE:		20070307
DATE AS OF CHANGE:		20070307

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			REINSCH PHILLIP A
		CENTRAL INDEX KEY:			0001227321

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-08896
		FILM NUMBER:		07678233

	MAIL ADDRESS:	
		STREET 1:		8401 N CENTRAL EXPRESSWAY
		STREET 2:		STE 800
		CITY:			DALLAS
		STATE:			TX
		ZIP:			75225

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			CAPSTEAD MORTGAGE CORP
		CENTRAL INDEX KEY:			0000766701
		STANDARD INDUSTRIAL CLASSIFICATION:	REAL ESTATE INVESTMENT TRUSTS [6798]
		IRS NUMBER:				752027937
		STATE OF INCORPORATION:			MD
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		8401 NORTH CENTRAL EXPRESSWAY
		STREET 2:		STE 800
		CITY:			DALLAS
		STATE:			TX
		ZIP:			75225
		BUSINESS PHONE:		2148742323

	MAIL ADDRESS:	
		STREET 1:		8401 NORTH CENTRAL EXPRESSWAY
		STREET 2:		STE 800
		CITY:			DALLAS
		STATE:			TX
		ZIP:			75225

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	LOMAS MORTGAGE CORP
		DATE OF NAME CHANGE:	19891105
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgardoc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2007-03-05</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000766701</issuerCik>
        <issuerName>CAPSTEAD MORTGAGE CORP</issuerName>
        <issuerTradingSymbol>CMO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001227321</rptOwnerCik>
            <rptOwnerName>REINSCH PHILLIP A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>8401 N. CENTRAL EXPRESSWAY</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 800</rptOwnerStreet2>
            <rptOwnerCity>DALLAS</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75225</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Executive Vice President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Series B Convertible Preferred</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2007-03-05</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>800</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>12.784</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>478</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2500</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>by Spouse</value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeHolding>
            <securityTitle>
                <value>Series B Convertible Preferred</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1743.72</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The Capstead $1.26 Cumulative Convertible Preferred Stock, Series B, is traded on the New York Stock exchange under the symbol CMOPRB.  The preferred stock is perpetual and is convertible into the Capstead common stock at any time at the stockholder's option.  The preferred stock is callable at the option of the company at $12.50 per share and an exercise date and price are not applicable.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Phillip A. Reinsch</signatureName>
        <signatureDate>2007-03-07</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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