SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                               -----------------


                                    FORM 8-K

                                 CURRENT REPORT
                       PURSUANT TO SECTION 13 OR 15 (d) OF
                       THE SECURITIES EXCHANGE ACT OF 1934


        Date of Report (Date of earliest event reported): April 20, 2005

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                                   ATMI, INC.
             (Exact name of registrant as specified in its charter)

           Delaware                       1-16239                06-1481060
 (State or other jurisdiction of   (Commission file number)   (I.R.S. employer
 incorporation or organization)                              identification no.)

          7 Commerce Drive
         Danbury, Connecticut                                         06810
 (Address of principal executive offices)                           (Zip code)


       Registrant's telephone number, including area code: (203) 794-1100


Check the appropriate box below if the Form 8-K filing is intended to
simultaneously satisfy the filing obligation of the registrant under any of the
following provisions (see General Instruction A.2. below):

[  ]  Written communications pursuant to Rule 425 under the Securities Act (17
      CFR 230.425)

[  ]  Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR
      240.14a-12)

[  ]  Pre-commencement communications pursuant to Rule 14d-2(b) under the
      Exchange Act (17 CFR 240.14d-2(b))

[  ]  Pre-commencement communications pursuant to Rule 13e-4(c) under the
      Exchange Act (17 CFR 240.13e-4(c))

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Item 2.02   Results of Operations and Financial Condition.

      On April 20, 2005, the Registrant issued a press release announcing its
financial results for the first quarter of 2005. A copy of the press release is
furnished as Exhibit 99.1 to this Current Report and is incorporated herein by
reference.

      The information in this Current Report on Form 8-K, including the exhibit,
is furnished and shall not be deemed "filed" for purposes of Section 18 of the
Securities Exchange Act of 1934, as amended, or otherwise subject to the
liabilities under that Section, and shall not be deemed to be incorporated by
reference into the filings of the Company under the Securities Act of 1933, as
amended, regardless of any general incorporation language in such filings.

Item 9.01 Exhibits.

      (a)   Not applicable.

      (b)   Not applicable.

      (c)   Exhibits

            Exhibit No.    Description
            -----------    -----------

            99.1           Press Release, dated April 20, 2005, entitled "ATMI
                           Reports First Quarter Financial Results."







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                                    SIGNATURE

      Pursuant to the requirements of the Securities Exchange Act of 1934, ATMI,
Inc. has duly caused this report to be signed on its behalf by the undersigned
hereunto duly authorized.

Date: April 20, 2005

                                       ATMI, INC.


                                       By: /s/ Daniel P. Sharkey
                                          -------------------------------------
                                          Name:  Daniel P. Sharkey
                                          Title: Vice President, Treasurer and
                                                 Chief Financial Officer