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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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 9MlEo5iClcnKJIYNbYUDmw==

<SEC-DOCUMENT>0001094718-08-000001.txt : 20080107
<SEC-HEADER>0001094718-08-000001.hdr.sgml : 20080107
<ACCEPTANCE-DATETIME>20080107143503
ACCESSION NUMBER:		0001094718-08-000001
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20080104
FILED AS OF DATE:		20080107
DATE AS OF CHANGE:		20080107

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			KRATOS DEFENSE & SECURITY SOLUTIONS, INC.
		CENTRAL INDEX KEY:			0001069258
		STANDARD INDUSTRIAL CLASSIFICATION:	COMMUNICATION SERVICES, NEC [4899]
		IRS NUMBER:				133818604
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		4810 EASTGATE MALL
		STREET 2:		.
		CITY:			SAN DIEGO
		STATE:			CA
		ZIP:			92121
		BUSINESS PHONE:		858-812-7300

	MAIL ADDRESS:	
		STREET 1:		4810 EASTGATE MALL
		STREET 2:		.
		CITY:			SAN DIEGO
		STATE:			CA
		ZIP:			92121

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	WIRELESS FACILITIES INC
		DATE OF NAME CHANGE:	19990817

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			LUND DEANNA HOM
		CENTRAL INDEX KEY:			0001094718

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-27231
		FILM NUMBER:		08514714

	BUSINESS ADDRESS:	
		STREET 1:		3033 SCIENCE PARK ROAD
		CITY:			SAN DIEGO
		STATE:			CA
		ZIP:			92121
		BUSINESS PHONE:		858-228-2000

	MAIL ADDRESS:	
		STREET 1:		4810 EASTGATE MALL
		CITY:			SAN DIEGO
		STATE:			CA
		ZIP:			92121

	FORMER NAME:	
		FORMER CONFORMED NAME:	HOM DEANNA
		DATE OF NAME CHANGE:	20030702

	FORMER NAME:	
		FORMER CONFORMED NAME:	PETERSEN DEANNA HOM
		DATE OF NAME CHANGE:	19990913
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-01-04</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001069258</issuerCik>
        <issuerName>KRATOS DEFENSE &amp; SECURITY SOLUTIONS, INC.</issuerName>
        <issuerTradingSymbol>KTOS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001094718</rptOwnerCik>
            <rptOwnerName>LUND DEANNA HOM</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>4810 EASTGATE MALL</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SAN DIEGO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>92121</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Senior Vice President &amp; CFO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2008-01-04</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>100000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2018-01-04</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>100000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>400000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Each restricted stock unit represents a contingent right to receive one share of issuer's common stock.</footnote>
        <footnote id="F2">The restricted stock units vest at the earlier of (a) 10 years from the date of grant; (b) upon a change in control of the issuer; or (c) upon termination of employment without cause. Vested shares will be delivered to the reporting person on the first date which is administratively practicable for the distribution of the vested shares after termination of service with the issuer.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Matthew G. Colvin, Attorney-In-Fact for Deanna Lund</signatureName>
        <signatureDate>2008-01-07</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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