<SEC-DOCUMENT>0001615216-17-000046.txt : 20171002
<SEC-HEADER>0001615216-17-000046.hdr.sgml : 20171002
<ACCEPTANCE-DATETIME>20171002103903
ACCESSION NUMBER:		0001615216-17-000046
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		2
CONFORMED PERIOD OF REPORT:	20170922
FILED AS OF DATE:		20171002
DATE AS OF CHANGE:		20171002

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Lewis Richard Brent
		CENTRAL INDEX KEY:			0001718260

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-07891
		FILM NUMBER:		171113377

	MAIL ADDRESS:	
		STREET 1:		PO BOX 1299
		CITY:			MINNEAPOLIS
		STATE:			MN
		ZIP:			55440

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			DONALDSON CO INC
		CENTRAL INDEX KEY:			0000029644
		STANDARD INDUSTRIAL CLASSIFICATION:	INDUSTRIAL & COMMERCIAL FANS & BLOWERS & AIR PURIFYING EQUIP [3564]
		IRS NUMBER:				410222640
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			0731

	BUSINESS ADDRESS:	
		STREET 1:		1400 W. 94TH ST.
		CITY:			MINNEAPOLIS
		STATE:			MN
		ZIP:			55431
		BUSINESS PHONE:		6128873131

	MAIL ADDRESS:	
		STREET 1:		1400 W 94TH STREET
		CITY:			MINNEAPOLIS
		STATE:			MN
		ZIP:			55431
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2017-09-22</periodOfReport>

    <issuer>
        <issuerCik>0000029644</issuerCik>
        <issuerName>DONALDSON CO INC</issuerName>
        <issuerTradingSymbol>DCI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001718260</rptOwnerCik>
            <rptOwnerName>Lewis Richard Brent</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1400 WEST 94TH STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>BLOOMINGTON</rptOwnerCity>
            <rptOwnerState>MN</rptOwnerState>
            <rptOwnerZipCode>55413</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Vice President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>343</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Benefit Plan Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2575</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>By Benefit Plan Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Emplyee Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>45.43</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2017-09-22</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>8600</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <value>2027-09-22</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>8600</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>8600</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The option vests in three equal annual installments beginning on Septebmer 22, 2018.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Amy C. Becker, Attorney-in-fact for Richard B. Lewis</signatureName>
        <signatureDate>2017-10-02</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-24
<SEQUENCE>2
<FILENAME>poalewis.htm
<DESCRIPTION>POA
<TEXT>
<HTML><BODY><PRE>POWER OF ATTORNEY







 KNOW ALL PERSONS BY THESE PRESENTS, that I, Richard B. Lewis

hereby constitute and appoint Amy C. Becker, Scott J. Robinson,

Melissa A. Osland, and Tod E. Carpenter, and each of them, my true and

lawful attorneys-in-fact and agents, each acting alone, with full

powers of substitution and resubstitution, for me and in my name,

place and stead, to sign any reports on Form 3 (Initial Statement

of Beneficial Ownership of Securities), Form 4 (Statement of Changes

in Beneficial Ownership of Securities) and Form 5 (Annual Statement

of Changes in Beneficial Ownership) relating to transactions by me

in Common Stock or other securities of Donaldson Company, Inc., and

all amendments thereto, and to file the same, with the Securities

and Exchange Commission and the New York Stock Exchange, Inc.,

granting unto said attorneys-in-fact and agents, and each of them,

or their substitutes, full power and authority to do and perform

each and every act and thing requisite or necessary to be done, as

fully to all intents and purposes as I might or could do in person,

hereby ratifying and confirming all that said attorneys-in-fact

and agents, and each of them, or their substitutes, may lawfully

do or cause to be done by virtue hereof.  This Power of Attorney

shall be effective until such time as I deliver a written revocation

thereof to the above-named attorneys-in-fact and agents.





Dated: September 22, 2017







/s/Richard B. Lewis

(signature)

Richard B. Lewis </PRE></BODY></HTML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
