-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
 MFgwCgYEVQgBAQICAf8DSgAwRwJAW2sNKK9AVtBzYZmr6aGjlWyK3XmZv3dTINen
 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 EvDlPyI5GAY4Ftg8flP5tdwN4xnqRACVwevQMtUjeAI11PRBSHzfPAThgEgoMgBP
 LmQ5oz2BduOxM+xASWNg/A==

<SEC-DOCUMENT>0000052466-03-000042.txt : 20030620
<SEC-HEADER>0000052466-03-000042.hdr.sgml : 20030620
<ACCEPTANCE-DATETIME>20030620095555
ACCESSION NUMBER:		0000052466-03-000042
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20030618
FILED AS OF DATE:		20030620

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			PAPASTAVROS THEODORE G
		CENTRAL INDEX KEY:			0001162765

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-07211
		FILM NUMBER:		03751000

	BUSINESS ADDRESS:	
		STREET 1:		65 GROVE STREET
		CITY:			WATERTOWN
		STATE:			MA
		ZIP:			02472

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			IONICS INC
		CENTRAL INDEX KEY:			0000052466
		STANDARD INDUSTRIAL CLASSIFICATION:	SPECIAL INDUSTRY MACHINERY, NEC [3559]
		IRS NUMBER:				042068530
		STATE OF INCORPORATION:			MA
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		65 GROVE ST
		CITY:			WATERTOWN
		STATE:			MA
		ZIP:			02172
		BUSINESS PHONE:		6179262500
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>tpapform4june20-2003_ex.xml
<TEXT>
<XML>
<?xml version="1.0"?>
<!-- - EDGAR Ease Plus 1.0                                   04/22/03  TZ    -->
<ownershipDocument>
    <schemaVersion>X0101</schemaVersion>

    <documentType>4</documentType>
   <periodOfReport>2003-06-18</periodOfReport>
   <notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0000052466</issuerCik>
        <issuerName>IONICS INC</issuerName>
        <issuerTradingSymbol>ION</issuerTradingSymbol>
   </issuer>
   <reportingOwner>
      <reportingOwnerId>
            <rptOwnerCik>0001162765</rptOwnerCik>
            <rptOwnerName>PAPASTAVROS THEODORE G</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
         <isDirector>0</isDirector>
         <isOfficer>1</isOfficer>
         <isTenPercentOwner>0</isTenPercentOwner>
         <isOther>0</isOther>
         <officerTitle>Executive VP and Treasurer</officerTitle>
       </reportingOwnerRelationship>
   </reportingOwner>
   <nonDerivativeSecurity>
      <securityTitle>
         <value>Common Stock</value>
      </securityTitle>
      <transactionDate>
         <value>2003-06-18</value>
      </transactionDate>
      <transactionCoding>
         <transactionFormType>4</transactionFormType>
         <transactionCode>M</transactionCode>
         <equitySwapInvolved>0</equitySwapInvolved>
      </transactionCoding>
      <transactionAmounts>
         <transactionShares>
           <value>3000</value>
         </transactionShares>
         <transactionValue>
           <value>19.75</value>
         </transactionValue>
         <transactionAcquiredDisposedCode>
           <value>A</value>
         </transactionAcquiredDisposedCode>
      </transactionAmounts>
     <postTransactionAmounts>
         <sharesOwnedFollowingTransaction>
           <value>72660</value>
         </sharesOwnedFollowingTransaction>
      </postTransactionAmounts>
      <ownershipNature>
         <directOrIndirectOwnership>
            <value>D</value>
         </directOrIndirectOwnership>
      </ownershipNature>
   </nonDerivativeSecurity>
   <nonDerivativeSecurity>
      <securityTitle>
         <value>Common Stock</value>
      </securityTitle>
      <transactionDate>
         <value>2003-06-18</value>
      </transactionDate>
      <transactionCoding>
         <transactionFormType>4</transactionFormType>
         <transactionCode>S</transactionCode>
         <equitySwapInvolved>0</equitySwapInvolved>
      </transactionCoding>
      <transactionAmounts>
         <transactionShares>
           <value>3000</value>
         </transactionShares>
         <transactionValue>
           <value>23.35</value>
         </transactionValue>
         <transactionAcquiredDisposedCode>
           <value>D</value>
         </transactionAcquiredDisposedCode>
      </transactionAmounts>
     <postTransactionAmounts>
         <sharesOwnedFollowingTransaction>
           <value>69660</value>
         </sharesOwnedFollowingTransaction>
      </postTransactionAmounts>
      <ownershipNature>
         <directOrIndirectOwnership>
            <value>D</value>
         </directOrIndirectOwnership>
      </ownershipNature>
   </nonDerivativeSecurity>
   <nonDerivativeSecurity>
      <securityTitle>
         <value>Common Stock</value>
      </securityTitle>
      <transactionDate>
         <value>2003-06-19</value>
      </transactionDate>
      <transactionCoding>
         <transactionFormType>4</transactionFormType>
         <transactionCode>M</transactionCode>
         <equitySwapInvolved>0</equitySwapInvolved>
      </transactionCoding>
      <transactionAmounts>
         <transactionShares>
           <value>3000</value>
         </transactionShares>
         <transactionValue>
           <value>19.75</value>
         </transactionValue>
         <transactionAcquiredDisposedCode>
           <value>A</value>
         </transactionAcquiredDisposedCode>
      </transactionAmounts>
     <postTransactionAmounts>
         <sharesOwnedFollowingTransaction>
           <value>72660</value>
         </sharesOwnedFollowingTransaction>
      </postTransactionAmounts>
      <ownershipNature>
         <directOrIndirectOwnership>
            <value>D</value>
         </directOrIndirectOwnership>
      </ownershipNature>
   </nonDerivativeSecurity>
   <nonDerivativeSecurity>
      <securityTitle>
         <value>Common Stock</value>
      </securityTitle>
      <transactionDate>
         <value>2003-06-19</value>
      </transactionDate>
      <transactionCoding>
         <transactionFormType>4</transactionFormType>
         <transactionCode>S</transactionCode>
         <equitySwapInvolved>0</equitySwapInvolved>
      </transactionCoding>
      <transactionAmounts>
         <transactionShares>
           <value>1300</value>
         </transactionShares>
         <transactionValue>
           <value>23.30</value>
         </transactionValue>
         <transactionAcquiredDisposedCode>
           <value>D</value>
         </transactionAcquiredDisposedCode>
      </transactionAmounts>
     <postTransactionAmounts>
         <sharesOwnedFollowingTransaction>
           <value>71360</value>
         </sharesOwnedFollowingTransaction>
      </postTransactionAmounts>
      <ownershipNature>
         <directOrIndirectOwnership>
            <value>D</value>
         </directOrIndirectOwnership>
      </ownershipNature>
   </nonDerivativeSecurity>
   <nonDerivativeSecurity>
      <securityTitle>
         <value>Common Stock</value>
      </securityTitle>
      <transactionDate>
         <value>2003-06-19</value>
      </transactionDate>
      <transactionCoding>
         <transactionFormType>4</transactionFormType>
         <transactionCode>S</transactionCode>
         <equitySwapInvolved>0</equitySwapInvolved>
      </transactionCoding>
      <transactionAmounts>
         <transactionShares>
           <value>900</value>
         </transactionShares>
         <transactionValue>
           <value>23.32</value>
         </transactionValue>
         <transactionAcquiredDisposedCode>
           <value>D</value>
         </transactionAcquiredDisposedCode>
      </transactionAmounts>
     <postTransactionAmounts>
         <sharesOwnedFollowingTransaction>
           <value>70460</value>
         </sharesOwnedFollowingTransaction>
      </postTransactionAmounts>
      <ownershipNature>
         <directOrIndirectOwnership>
            <value>D</value>
         </directOrIndirectOwnership>
      </ownershipNature>
   </nonDerivativeSecurity>
   <nonDerivativeSecurity>
      <securityTitle>
         <value>Common Stock</value>
      </securityTitle>
      <transactionDate>
         <value>2003-06-19</value>
      </transactionDate>
      <transactionCoding>
         <transactionFormType>4</transactionFormType>
         <transactionCode>S</transactionCode>
         <equitySwapInvolved>0</equitySwapInvolved>
      </transactionCoding>
      <transactionAmounts>
         <transactionShares>
           <value>100</value>
         </transactionShares>
         <transactionValue>
           <value>23.38</value>
         </transactionValue>
         <transactionAcquiredDisposedCode>
           <value>D</value>
         </transactionAcquiredDisposedCode>
      </transactionAmounts>
     <postTransactionAmounts>
         <sharesOwnedFollowingTransaction>
           <value>70360</value>
         </sharesOwnedFollowingTransaction>
      </postTransactionAmounts>
      <ownershipNature>
         <directOrIndirectOwnership>
            <value>D</value>
         </directOrIndirectOwnership>
      </ownershipNature>
   </nonDerivativeSecurity>
   <nonDerivativeSecurity>
      <securityTitle>
         <value>Common Stock</value>
      </securityTitle>
      <transactionDate>
         <value>2003-06-19</value>
      </transactionDate>
      <transactionCoding>
         <transactionFormType>4</transactionFormType>
         <transactionCode>S</transactionCode>
         <equitySwapInvolved>0</equitySwapInvolved>
      </transactionCoding>
      <transactionAmounts>
         <transactionShares>
           <value>700</value>
         </transactionShares>
         <transactionValue>
           <value>23.00</value>
         </transactionValue>
         <transactionAcquiredDisposedCode>
           <value>D</value>
         </transactionAcquiredDisposedCode>
      </transactionAmounts>
     <postTransactionAmounts>
         <sharesOwnedFollowingTransaction>
           <value>69660</value>
         </sharesOwnedFollowingTransaction>
      </postTransactionAmounts>
      <ownershipNature>
         <directOrIndirectOwnership>
            <value>D</value>
            <footnoteId id="F1"/>
         </directOrIndirectOwnership>
      </ownershipNature>
   </nonDerivativeSecurity>
   <derivativeSecurity>
      <securityTitle>
         <value>Stock Option (right to buy)</value>
      </securityTitle>
      <conversionOrExercisePrice>
         <value>19.75</value>
      </conversionOrExercisePrice>
      <transactionDate>
         <value>2003-06-18</value>
      </transactionDate>
      <transactionCoding>
         <transactionFormType>4</transactionFormType>
         <transactionCode>M</transactionCode>
         <equitySwapInvolved>0</equitySwapInvolved>
            <footnoteId id="F2"/>
      </transactionCoding>
      <transactionAmounts>
         <transactionShares>
           <value>3000</value>
         </transactionShares>
         <transactionValue>
           <value>19.75</value>
         </transactionValue>
         <transactionAcquiredDisposedCode>
           <value>D</value>
         </transactionAcquiredDisposedCode>
      </transactionAmounts>
      <exerciseDate>
         <value>1993-08-25</value>
      </exerciseDate>
      <expirationDate>
         <value>2003-08-25</value>
      </expirationDate>
      <underlyingSecurity>
         <underlyingSecurityTitle>
           <value>Common Stock</value>
         </underlyingSecurityTitle>
         <underlyingSecurityShares>
           <value>3000</value>
         </underlyingSecurityShares>
      </underlyingSecurity>
      <postTransactionAmounts>
         <sharesOwnedFollowingTransaction>
           <value>17000</value>
         </sharesOwnedFollowingTransaction>
      </postTransactionAmounts>
      <ownershipNature>
         <directOrIndirectOwnership>
           <value>D</value>
         </directOrIndirectOwnership>
      </ownershipNature>
   </derivativeSecurity>
   <derivativeSecurity>
      <securityTitle>
         <value>Stock Option (right to buy)</value>
      </securityTitle>
      <conversionOrExercisePrice>
         <value>19.75</value>
      </conversionOrExercisePrice>
      <transactionDate>
         <value>2003-06-19</value>
      </transactionDate>
      <transactionCoding>
         <transactionFormType>4</transactionFormType>
         <transactionCode>M</transactionCode>
         <equitySwapInvolved>0</equitySwapInvolved>
            <footnoteId id="F2"/>
      </transactionCoding>
      <transactionAmounts>
         <transactionShares>
           <value>3000</value>
         </transactionShares>
         <transactionValue>
           <value>19.75</value>
         </transactionValue>
         <transactionAcquiredDisposedCode>
           <value>D</value>
         </transactionAcquiredDisposedCode>
      </transactionAmounts>
      <exerciseDate>
         <value>1993-08-25</value>
      </exerciseDate>
      <expirationDate>
         <value>2003-08-25</value>
      </expirationDate>
      <underlyingSecurity>
         <underlyingSecurityTitle>
           <value>Common Stock</value>
         </underlyingSecurityTitle>
         <underlyingSecurityShares>
           <value>3000</value>
         </underlyingSecurityShares>
      </underlyingSecurity>
      <postTransactionAmounts>
         <sharesOwnedFollowingTransaction>
           <value>14000</value>
         </sharesOwnedFollowingTransaction>
      </postTransactionAmounts>
      <ownershipNature>
         <directOrIndirectOwnership>
           <value>D</value>
         </directOrIndirectOwnership>
      </ownershipNature>
   </derivativeSecurity>
   <footnotes>
<footnote id="F1"> Reporting person also indirectly owns 4809 shares acquired from time to time as a result of reporting person's participation in Ionics Section 401(k) Plan (shares are held in name of trustee).</footnote>

<footnote id="F2"> Option granted under Ionics, Incorporated 1979 Stock Option Plan in a transaction exempt under Rule 16b-3.</footnote>
   </footnotes>
   <ownerSignature>
      <signatureName>Theodore G. Papastavros</signatureName>
      <signatureDate>2003-06-20</signatureDate>
   </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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