<SEC-DOCUMENT>0000914122-14-000008.txt : 20140409
<SEC-HEADER>0000914122-14-000008.hdr.sgml : 20140409
<ACCEPTANCE-DATETIME>20140409121212
ACCESSION NUMBER:		0000914122-14-000008
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20140404
FILED AS OF DATE:		20140409
DATE AS OF CHANGE:		20140409

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MFRI INC
		CENTRAL INDEX KEY:			0000914122
		STANDARD INDUSTRIAL CLASSIFICATION:	INDUSTRIAL & COMMERCIAL FANS & BLOWERS & AIR PURIFYING EQUIP [3564]
		IRS NUMBER:				363922969
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0131

	BUSINESS ADDRESS:	
		STREET 1:		7720 LEHIGH AVE
		CITY:			NILES
		STATE:			IL
		ZIP:			60714
		BUSINESS PHONE:		8479661000

	MAIL ADDRESS:	
		STREET 1:		7720 LEHIGH AVE
		CITY:			NILES
		STATE:			IL
		ZIP:			60714

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	MIDWESCO FILTER RESOURCES INC
		DATE OF NAME CHANGE:	19970402

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SCHMIDT KARL J
		CENTRAL INDEX KEY:			0001202469

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-32530
		FILM NUMBER:		14752962

	MAIL ADDRESS:	
		STREET 1:		7720 N. LEHIGH AVE
		CITY:			NILES
		STATE:			IL
		ZIP:			60714-3491
</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>2014-04-04</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000914122</issuerCik>
        <issuerName>MFRI INC</issuerName>
        <issuerTradingSymbol>MFRI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001202469</rptOwnerCik>
            <rptOwnerName>SCHMIDT KARL J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>7720 N. LEHIGH AVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NILES</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60714-3491</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Officer, VP, CFO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Deferred Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2014-04-04</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>5062</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>13.53</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>5062</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5062</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Deferred Stock Units earned by the reporting person by elective deferral of exectuive officer incentive compensation, pursuant to the Company's Deferred Stock Purchase Plan.  The Deferred Stock Units are payable to the reporting person in Common Stock on a one-for-one basis, upon the first business day of the fiscal year following the fiscal year of separation of service,however, no distribution will be made prior to the date that is six months following separation from service to the extent the reporting person qualifies as a specified employee.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Karl J Schmidt</signatureName>
        <signatureDate>2014-04-09</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
