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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,
 CvFBj2+/Pwx3J2df+9+7yKy9hxz3UsLTsa7NYFpT0N3Ge9/7eNuqKamOhgtUtq8Z
 y/m9EkjBVT0KhifrY08j+Q==

<SEC-DOCUMENT>0001144204-08-060626.txt : 20081103
<SEC-HEADER>0001144204-08-060626.hdr.sgml : 20081103
<ACCEPTANCE-DATETIME>20081103110703
ACCESSION NUMBER:		0001144204-08-060626
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20081103
FILED AS OF DATE:		20081103
DATE AS OF CHANGE:		20081103

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:			Carlson Timothy C
		CENTRAL INDEX KEY:			0001392394

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-16239
		FILM NUMBER:		081156417

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		203 767-9068

	MAIL ADDRESS:	
		STREET 1:		6 FRONWOOD ROAD
		CITY:			SANDY HOOK
		STATE:			CT
		ZIP:			06482
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>form418075_110308110610-.xml
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-11-03</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001392394</rptOwnerCik>
            <rptOwnerName>Carlson Timothy C</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>6 COMMERCE DR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>DANBURY</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>US 06810</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CFO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-11-03</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1500</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>12.964</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>40147</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <ownerSignature>
        <signatureName>/s/Timothy Carlson</signatureName>
        <signatureDate>2008-11-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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