EXHIBIT 99.1

ATMI Reports Revenue and Earnings Growth for Second Quarter 2012

Record Revenue Driven by SDS Direct and LifeSciences Growth

DANBURY, Conn., July 25, 2012 (GLOBE NEWSWIRE) -- ATMI, Inc. (Nasdaq:ATMI) today reported financial results for the second quarter of 2012.

Revenues grew to $105.9 million during the second quarter of 2012 compared with $104.0 million last year, primarily due to the positive contribution from the SDS^® Direct transaction completed last year and single-use consumables growth in LifeSciences. Net income for the quarter was $11.4 million, or $0.35 per diluted share, compared with $11.1 million, or $0.34 per diluted share, during the prior year period. The SDS^® Direct transaction added net revenues of $5.8 million and net income of $2.5 million, or $0.08 per diluted share.

"In Microelectronics, the positive contribution from our SDS^® Direct transaction offset lower revenues for display and some older copper products," said Doug Neugold, Chief Executive Officer. "While the overall market environment is uncertain, we continue to see momentum at the leading edge, notably in areas supporting smartphone and tablet demand. In addition to this, we achieved significant LifeSciences growth as our customers continued to migrate towards single-use technology, driving demand for our consumable mixers and bioreactors."

Gross margin was 50.5 percent during the second quarter compared with 47.5 percent last year as a result of SDS^® Direct. Operating margin was 16.0 percent in the second quarter of 2012 compared to 14.8 percent last year. Net cash provided by operating activities improved 79 percent to $22.6 million in the second quarter of 2012 compared with $12.7 million in the second quarter a year ago.

Segment Results (all comparisons to same period in 2011)

Microelectronics

• Revenues were unchanged at $94.6 million
• SDS^® growth offset by lower revenues for display and some older copper products
• Operating income grew more than 7 percent due to SDS^® impact

LifeSciences

• Revenues surged 19 percent to $11.2 million
• Demand for higher margin consumable products continues to grow as customers migrate to high-volume manufacturing using single-use technology
• Operating loss reduced as higher volumes in consumables and resulting favorable mix improved margins

Outlook

"While we pay close attention to the growing uncertainty as it relates to second half demand, we remain confident in our ability to achieve meaningful growth for the balance of the year," commented Neugold. "We see wafer starts for 2012 modestly stronger than 2011, with typical seasonal patterns expected during the second half. Our customers are continuing to ramp and develop leading-edge technology nodes, and we are working with them to help them solve their material challenges. The SDS^® Direct transition is behind us and we should experience full-quarter benefits going forward. Our LifeSciences customers continue to move to high-volume production using our single-use technology, although the third quarter is typically affected by the seasonal business cycle in Europe."

Webcast Information

A conference call (dial-in: 877.766.0748) discussing the Company's financial results and business outlook will begin at 11:00 a.m. Eastern time, July 25, 2012. A replay of the call will be available for 48 hours at 855.859.2056 (access code 41878232). An audio webcast of the conference call will be available for 30 days on http://investor.atmi.com.

About ATMI

ATMI, Inc. provides specialty semiconductor materials, and safe, high-purity materials handling and delivery solutions designed to increase process efficiencies for the worldwide semiconductor, flat panel, and life sciences industries. For more information, please visit http://www.atmi.com.

The ATMI, Inc. logo is available at http://www.globenewswire.com/newsroom/prs/?pkgid=5254

ATMI, the ATMI logo, and SDS are trademarks or registered trademarks of Advanced Technology Materials, Inc., in the United States, other countries, or both.

Forward Looking Statements

Statements contained herein that relate to ATMI's future performance, including, without limitation, statements with respect to ATMI's anticipated results of operations or level of business for 2012 or any other future period, are forward-looking statements within the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. Such statements are based on current expectations only and are subject to certain risks, uncertainties, and assumptions, including, but not limited to, changes in semiconductor and life sciences industry growth (including, without limitation, wafer starts) or ATMI's markets; competition, problems, or delays developing, commercializing, and delivering new products; customer-driven pricing pressure; potential loss of key customers; problems or delays in integrating acquired operations and businesses; uncertainty in the credit and financial markets; ability to protect ATMI's proprietary technology; and other factors described in ATMI's Form 10-K for the year ended December 31, 2011 and other subsequent filings with the Securities and Exchange Commission. Such risks and uncertainties may cause actual results to differ materially from those expressed in our forward-looking statements. ATMI undertakes no obligation to update any forward-looking statements.

CONTACT: Troy Dewar
         Director, Investor Relations
         203.207.9349
         tdewar@atmi.com