-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 STqKRdJJuiTaM/ta5IlGeiFLucoa/S6t3sBCi5q0SRRdIZfBt8IjAxG/ZFbzxrqL
 MhuxmEXlFX7BC6gTEI0MOw==

<SEC-DOCUMENT>0000897101-03-000874.txt : 20030731
<SEC-HEADER>0000897101-03-000874.hdr.sgml : 20030731
<ACCEPTANCE-DATETIME>20030731151555
ACCESSION NUMBER:		0000897101-03-000874
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20030729
FILED AS OF DATE:		20030731

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

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			PRIADKA NICKOLAS
		CENTRAL INDEX KEY:			0001226580

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-07891
		FILM NUMBER:		03814444

	BUSINESS ADDRESS:	
		STREET 1:		C/O DONALDSON CO INC
		STREET 2:		PO BOX 1299
		CITY:			MINNEAPOLIS
		STATE:			MN
		ZIP:			55440-1299
		BUSINESS PHONE:		9528873631
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>priadka_dci.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2003-07-29</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001226580</rptOwnerCik>
            <rptOwnerName>PRIADKA NICKOLAS</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1></rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity></rptOwnerCity>
            <rptOwnerState></rptOwnerState>
            <rptOwnerZipCode></rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>


            <officerTitle>Senior VP</officerTitle>

        </reportingOwnerRelationship>
    </reportingOwner>


	<nonDerivativeTable>


		<nonDerivativeTransaction>
			<securityTitle>
				<value>Common Stock</value>
			</securityTitle>
			<transactionDate>

				<value>2003-07-29</value>

			</transactionDate>

			<transactionCoding>
				<transactionFormType>4</transactionFormType>
				<transactionCode>M</transactionCode>

				<equitySwapInvolved>0</equitySwapInvolved>

			</transactionCoding>

			<transactionAmounts>
				<transactionShares>
					<value>22500</value>
				</transactionShares>
				<transactionPricePerShare>
					<value>35.54</value>
				</transactionPricePerShare>
				<transactionAcquiredDisposedCode>
					<value>A</value>
				</transactionAcquiredDisposedCode>
			</transactionAmounts>
			<postTransactionAmounts>

				<sharesOwnedFollowingTransaction>

					<value>0</value>

				</sharesOwnedFollowingTransaction>

			</postTransactionAmounts>

			<ownershipNature>
				<directOrIndirectOwnership>
					<value>D</value>
				</directOrIndirectOwnership>
			</ownershipNature>
		</nonDerivativeTransaction>


		<nonDerivativeTransaction>
			<securityTitle>
				<value>Common Stock</value>
			</securityTitle>
			<transactionDate>

				<value>2003-07-29</value>

			</transactionDate>

			<transactionCoding>
				<transactionFormType>4</transactionFormType>
				<transactionCode>F</transactionCode>

				<equitySwapInvolved>0</equitySwapInvolved>

			</transactionCoding>

			<transactionAmounts>
				<transactionShares>
					<value>18345</value>
				</transactionShares>
				<transactionPricePerShare>
					<value>48.30</value>
				</transactionPricePerShare>
				<transactionAcquiredDisposedCode>
					<value>D</value>
				</transactionAcquiredDisposedCode>
			</transactionAmounts>
			<postTransactionAmounts>

				<sharesOwnedFollowingTransaction>

					<value>171438</value>

				</sharesOwnedFollowingTransaction>

			</postTransactionAmounts>

			<ownershipNature>
				<directOrIndirectOwnership>
					<value>D</value>
				</directOrIndirectOwnership>
			</ownershipNature>
		</nonDerivativeTransaction>


		<nonDerivativeHolding>
			<securityTitle>
				<value>Common Stock</value>
			</securityTitle>
			<postTransactionAmounts>

				<sharesOwnedFollowingTransaction>

					<value>21693</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>1998</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>24358</value>

				</sharesOwnedFollowingTransaction>

			</postTransactionAmounts>

			<ownershipNature>
				<directOrIndirectOwnership>
					<value>I</value>
				</directOrIndirectOwnership>
				<natureOfOwnership>

					<value>By Trust</value>

				</natureOfOwnership>

			</ownershipNature>
		</nonDerivativeHolding>

	</nonDerivativeTable>



	<derivativeTable>


		<derivativeTransaction>
			<securityTitle>
				<value>Option (right to buy)</value>
			</securityTitle>
			<conversionOrExercisePrice>
				<value>35.56</value>
			</conversionOrExercisePrice>
			<transactionDate>

				<value>2003-07-29</value>

			</transactionDate>

			<transactionCoding>

				<transactionFormType>4</transactionFormType>

				<transactionCode>M</transactionCode>

				<equitySwapInvolved>0</equitySwapInvolved>

			</transactionCoding>

			<transactionAmounts>

				<transactionShares>

					<value>22500</value>

				</transactionShares>

				<transactionPricePerShare>

					<value>0</value>

				</transactionPricePerShare>

				<transactionAcquiredDisposedCode>

					<value>D</value>

				</transactionAcquiredDisposedCode>

			</transactionAmounts>

			<exerciseDate>

				<value>2002-12-05</value>

			</exerciseDate>

			<expirationDate>

				<value>2010-12-05</value>

			</expirationDate>

			<underlyingSecurity>

				<underlyingSecurityTitle>

					<value>Common Stock</value>

				</underlyingSecurityTitle>

				<underlyingSecurityShares>

					<value>22500</value>

				</underlyingSecurityShares>

			</underlyingSecurity>

			<postTransactionAmounts>

				<sharesOwnedFollowingTransaction>

					<value>0</value>

				</sharesOwnedFollowingTransaction>

			</postTransactionAmounts>

			<ownershipNature>

				<directOrIndirectOwnership>

				<value>D</value>

				</directOrIndirectOwnership>

			</ownershipNature>

		</derivativeTransaction>


		<derivativeTransaction>
			<securityTitle>
				<value>Option (right to buy)</value>
			</securityTitle>
			<conversionOrExercisePrice>
				<value>48.30</value>
			</conversionOrExercisePrice>
			<transactionDate>

				<value>2003-07-29</value>

			</transactionDate>

			<transactionCoding>

				<transactionFormType>4</transactionFormType>

				<transactionCode>A</transactionCode>

				<equitySwapInvolved>0</equitySwapInvolved>

			</transactionCoding>

			<transactionAmounts>

				<transactionShares>

					<value>18345</value>

				</transactionShares>

				<transactionPricePerShare>

					<value>0</value>

				</transactionPricePerShare>

				<transactionAcquiredDisposedCode>

					<value>A</value>

				</transactionAcquiredDisposedCode>

			</transactionAmounts>

			<exerciseDate>

				<value>2003-07-29</value>

			</exerciseDate>

			<expirationDate>

				<value>2010-12-05</value>

			</expirationDate>

			<underlyingSecurity>

				<underlyingSecurityTitle>

					<value>Common Stock</value>

				</underlyingSecurityTitle>

				<underlyingSecurityShares>

					<value>18345</value>

				</underlyingSecurityShares>

			</underlyingSecurity>

			<postTransactionAmounts>

				<sharesOwnedFollowingTransaction>

					<value>0</value>

				</sharesOwnedFollowingTransaction>

			</postTransactionAmounts>

			<ownershipNature>

				<directOrIndirectOwnership>

				<value>D</value>

				</directOrIndirectOwnership>

			</ownershipNature>

		</derivativeTransaction>

	</derivativeTable>


    <ownerSignature>
        <signatureName>Nickolas Priadka     /s/ Norman C. Linnell by Power of Attorney</signatureName>
        <signatureDate>2003-07-31</signatureDate>
    </ownerSignature>

</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
-----END PRIVACY-ENHANCED MESSAGE-----