Cabot Microelectronics Corporation Earns Supplier Award from Inotera Memories

Cabot Microelectronics Corporation (Nasdaq: CCMP), the world’s leading supplier of chemical mechanical planarization (CMP) polishing slurries and growing CMP pad supplier to the semiconductor industry, announced today that it has received an Outstanding Supplier Award for the second consecutive year from Taiwan-based Inotera Memories, Inc. (Inotera) for supplying CMP polishing slurries. This award is granted to suppliers who demonstrate excellence across a variety of areas, including product quality, cost of ownership, on-time delivery, world-class service, and a commitment to technology and safety.

William Noglows, Chairman and CEO of Cabot Microelectronics commented, "It is an honor to receive this award, which we believe reflects our strong commitment to help Inotera maintain its zero defects principle. As part of our three key initiatives of Technology Leadership, Operations Excellence and Connecting with Customers, we aim to continue to supply consistent, high performing products and provide responsive technical support to meet and exceed the needs of our customers.”

Charles Kau, President of Inotera Memories stated, "The success of Inotera cannot be achieved without close cooperation with our important partners; hence the annual outstanding supplier is awarded in return for great performance and contributions from Cabot Microelectronics in this past year”.

ABOUT CABOT MICROELECTRONICS CORPORATION

Cabot Microelectronics Corporation, headquartered in Aurora, Illinois, is the world's leading supplier of CMP polishing slurries and growing CMP pad supplier to the semiconductor industry. The company's products play a critical role in the production of the most advanced semiconductor devices, enabling the manufacture of smaller, faster and more complex devices by its customers. Since becoming an independent public company in 2000, the company has grown to approximately 900 employees globally. The company's vision is to become the world leader in shaping, enabling and enhancing the performance of surfaces, so the company is leveraging its expertise in CMP slurry formulation, materials and polishing techniques developed for the semiconductor industry and applying it to demanding surface modification applications in other industries where shaping, enabling and enhancing the performance of surfaces is critical to success. For more information about Cabot Microelectronics Corporation, visit www.cabotcmp.com or contact Amy Ford, Director of Investor Relations at (630) 499-2600.

SAFE HARBOR STATEMENT

This news release may include statements that constitute "forward looking statements” within the meaning of federal securities regulations. These forward-looking statements include statements related to: future sales and operating results; company and industry growth, contraction or trends; growth or contraction of the markets in which the company participates; international events or various economic factors; product performance; the generation, protection and acquisition of intellectual property, and litigation related to such intellectual property; new product introductions; development of new products, technologies and markets; the acquisition of or investment in other entities; uses and investment of the company’s cash balance; and the construction of facilities by Cabot Microelectronics Corporation. These forward-looking statements involve a number of risks, uncertainties, and other factors, including those described from time to time in Cabot Microelectronics’ filings with the Securities and Exchange Commission (SEC), that could cause actual results to differ materially from those described by these forward-looking statements. In particular, see "Risk Factors" in the company's quarterly report on Form 10-Q for the quarter ended March 31, 2009 and in the company's annual report on Form 10-K for the fiscal year ended September 30, 2008, both filed with the SEC. Cabot Microelectronics assumes no obligation to update this forward-looking information.