-----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,
 BSCtxlUfFFmKx57nqiJHA/GBrhzhArFKzzYPZpmYNgjc5MY9s86DvHLDq0sD8v1i
 c9psgKv8y8viFu4l1uBgYw==

<SEC-DOCUMENT>0001273820-04-000004.txt : 20040423
<SEC-HEADER>0001273820-04-000004.hdr.sgml : 20040423
<ACCEPTANCE-DATETIME>20040423124458
ACCESSION NUMBER:		0001273820-04-000004
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20040421
FILED AS OF DATE:		20040423

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			KEISER GARY
		CENTRAL INDEX KEY:			0001273820

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-08896
		FILM NUMBER:		04750182

	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>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-04-21</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001273820</rptOwnerCik>
            <rptOwnerName>KEISER GARY</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>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Nonqualified Director Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>14.41</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2004-04-21</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>5</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>10000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2004-04-21</value>
            </exerciseDate>
            <expirationDate>
                <value>2014-04-21</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>10000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>10000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Director stock option granted pursuant to the Capstead Mortgage Corporation 1994 Flexible Long Term Incentive Plan.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>By: Phillip A. Reinsch  For: Gary Keiser</signatureName>
        <signatureDate>2004-04-23</signatureDate>
    </ownerSignature>
</ownershipDocument>

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