<SEC-DOCUMENT>0001643526-18-000009.txt : 20180511
<SEC-HEADER>0001643526-18-000009.hdr.sgml : 20180511
<ACCEPTANCE-DATETIME>20180511153412
ACCESSION NUMBER:		0001643526-18-000009
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20180509
FILED AS OF DATE:		20180511
DATE AS OF CHANGE:		20180511

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			El Sadany Tarek
		CENTRAL INDEX KEY:			0001643526

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-08729
		FILM NUMBER:		18826640

	MAIL ADDRESS:	
		STREET 1:		801 LAKEVIEW DRIVE
		STREET 2:		SUITE 100
		CITY:			BLUE BELL
		STATE:			PA
		ZIP:			19422

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			UNISYS CORP
		CENTRAL INDEX KEY:			0000746838
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-COMPUTER INTEGRATED SYSTEMS DESIGN [7373]
		IRS NUMBER:				380387840
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		801 LAKEVIEW DRIVE, SUITE 100
		CITY:			BLUE BELL
		STATE:			PA
		ZIP:			19422
		BUSINESS PHONE:		2159864011

	MAIL ADDRESS:	
		STREET 1:		801 LAKEVIEW DRIVE, SUITE 100
		CITY:			BLUE BELL
		STATE:			PA
		ZIP:			19422

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	BURROUGHS CORP /DE/
		DATE OF NAME CHANGE:	19861204
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>primary_doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2018-05-09</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000746838</issuerCik>
        <issuerName>UNISYS CORP</issuerName>
        <issuerTradingSymbol>UIS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001643526</rptOwnerCik>
            <rptOwnerName>El Sadany Tarek</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>801 LAKEVIEW DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 100</rptOwnerStreet2>
            <rptOwnerCity>BLUE BELL</rptOwnerCity>
            <rptOwnerState>PA</rptOwnerState>
            <rptOwnerZipCode>19422</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Senior Vice President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2018-05-09</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>75</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>12.1</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>27772</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <ownerSignature>
        <signatureName>John M. Armbruster, attorney-in-fact</signatureName>
        <signatureDate>2018-05-11</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
