Press Release

AURORA, Ill.--(BUSINESS WIRE)--Oct. 28, 2005--Cabot Microelectronics Corporation (Nasdaq:CCMP), the leading supplier of chemical mechanical planarization (CMP) slurries to the semiconductor industry, announced today that it will make a presentation at the Deutsch Bank 2005 Global Semiconductor and Semi Capital Equipment Conference in Las Vegas, Nevada, at 6:15 p.m., Central time on Thursday, November 3, 2005. Forward looking and other material information may be discussed during the presentation. The presentation will be available to all interested parties via webcast from its site at www.cabotcmp.com. For those who cannot listen to the live broadcast, a copy of the presentation will be available in the Investor Relations section of the company's website at www.cabotcmp.com.

About Cabot Microelectronics

Cabot Microelectronics Corporation, headquartered in Aurora, Illinois, is the leading supplier of CMP slurries for polishing various materials used in semiconductor manufacturing processes. 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. For more information about Cabot Microelectronics Corporation visit www.cabotcmp.com or contact Investor Relations at (630) 499-2600.

    CONTACT: Cabot Microelectronics Corporation
             Barbara Ven Horst, 630-499-2600

    SOURCE: Cabot Microelectronics Corporation