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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 EL8Mm1OFAbb1JqYHctl+Gt+gNKyANKTWFQ1i4AASsNFDtUTncIFDiP6gTx2OW0WZ
 ioU5kLINemZoujPraQkrZw==

<SEC-DOCUMENT>0001144204-08-062937.txt : 20081112
<SEC-HEADER>0001144204-08-062937.hdr.sgml : 20081111
<ACCEPTANCE-DATETIME>20081112170050
ACCESSION NUMBER:		0001144204-08-062937
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20081112
FILED AS OF DATE:		20081112
DATE AS OF CHANGE:		20081112

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ATMI INC
		CENTRAL INDEX KEY:			0001041577
		STANDARD INDUSTRIAL CLASSIFICATION:	INDUSTRIAL INORGANIC CHEMICALS [2810]
		IRS NUMBER:				061481060
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		7 COMMERCE DRIVE
		CITY:			DANBURY
		STATE:			CT
		ZIP:			06810-4169
		BUSINESS PHONE:		2037941100

	MAIL ADDRESS:	
		STREET 1:		7 COMMERCE DRVIE
		CITY:			DANBURY
		STATE:			CT
		ZIP:			06810-4169

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ATMI HOLDINGS INC
		DATE OF NAME CHANGE:	19970625

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			McGowan Thomas J
		CENTRAL INDEX KEY:			0001393232

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-16239
		FILM NUMBER:		081181607

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		203 888-1947

	MAIL ADDRESS:	
		STREET 1:		15 OLD FARM ROAD
		CITY:			OXFORD
		STATE:			CT
		ZIP:			06478
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>v131749_ex.xml
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-11-12</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0001041577</issuerCik>
        <issuerName>ATMI INC</issuerName>
        <issuerTradingSymbol>ATMI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001393232</rptOwnerCik>
            <rptOwnerName>McGowan Thomas J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>6 COMMERCE DR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>DANBURY</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06810</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>VP, HR/OD</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <ownerSignature>
        <signatureName>/s/Thomas McGowan</signatureName>
        <signatureDate>2008-11-12</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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