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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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<SEC-DOCUMENT>0001428642-10-000018.txt : 20100429
<SEC-HEADER>0001428642-10-000018.hdr.sgml : 20100429
<ACCEPTANCE-DATETIME>20100429123908
ACCESSION NUMBER:		0001428642-10-000018
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20100428
FILED AS OF DATE:		20100429
DATE AS OF CHANGE:		20100429

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			DUFFY W LESLIE
		CENTRAL INDEX KEY:			0001227816

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-07665
		FILM NUMBER:		10780118

	MAIL ADDRESS:	
		STREET 1:		C/O CAHILL GORDON & REINDEL
		STREET 2:		80 PINE STREET 19TH FLOOR
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10005

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			LYDALL INC /DE/
		CENTRAL INDEX KEY:			0000060977
		STANDARD INDUSTRIAL CLASSIFICATION:	MOTOR VEHICLE PARTS & ACCESSORIES [3714]
		IRS NUMBER:				060865505
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		ONE COLONIAL RD
		STREET 2:		P O BOX 151
		CITY:			MANCHESTER
		STATE:			CT
		ZIP:			06045-0151
		BUSINESS PHONE:		2036461233

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	COLONIAL BOARD CO
		DATE OF NAME CHANGE:	19700115
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-04-28</periodOfReport>

    <issuer>
        <issuerCik>0000060977</issuerCik>
        <issuerName>LYDALL INC /DE/</issuerName>
        <issuerTradingSymbol>LDL</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001227816</rptOwnerCik>
            <rptOwnerName>DUFFY W LESLIE</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O LYDALL, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>ONE COLONIAL ROAD</rptOwnerStreet2>
            <rptOwnerCity>MANCHESTER</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06042</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Option to Buy</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>8.65</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2010-04-28</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>325</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2011-04-28</value>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2020-04-27</value>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>325</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>325</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Option to Buy</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>8.65</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2010-04-28</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2011-04-28</value>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2020-04-27</value>
                <footnoteId id="F4"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>3000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Non-qualified stock options granted under the Amended and Restated Lydall 2003 Stock Incentive Compensation Plan.  These options are granted automatically on the date of the Annual Meeting of Shareholders to each person then serving as an Outside Director of the Issuer and become exercisable in three equal installments commencing on the first anniversary of the date of grant.</footnote>
        <footnote id="F2">Options are exercisable until the earlier of ten years from date of grant or a period of three years from the date on which such person ceases to be a Director of the Issuer.</footnote>
        <footnote id="F3">Non-qualified stock options granted under the Amended and Restated Lydall 2003 Stock Incentive Compensation Plan.  These options are granted automatically on the date of the Annual Meeting of Shareholders to each person then serving as an Outside Director of the Issuer and become exercisable in four equal annual installments commencing as of the first anniversary of the date of grant.</footnote>
        <footnote id="F4">Options are exercisable until the earlier of ten years from date of grant or a period of three months from the date such person ceases to be a Director of the Issuer (for any reason other than death).</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Paul G. Igoe, Attorney-in-fact for W. Leslie Duffy</signatureName>
        <signatureDate>2010-04-29</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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