BT and Leading Industry Analyst Firms to Headline Micromuse's 2005 North American Netcool(R) Users Conference.

SAN FRANCISCO -- Micromuse Inc. (Nasdaq: MUSE), the leading provider of ultra-scalable, realtime business and service assurance software, today announced an all-star line-up of keynote speakers for its Netcool(R) Users Conference, to be held October 25 - 27, 2005 in New York City. With keynote presentations from BT, IDC, and Gartner this year's event will examine the industry and technology trends that are influencing today's service provider and enterprise markets. Keynote presenters at next week's conference will include:

--Phill Radley, Head of Network Reporting Design at BT, will describe how BT's ambitious 21CN (21st-century network) initiative will be underpinned by a highly scalable and flexible reporting infrastructure to assure service performance and availability.

--Chris Christiansen, IDC analyst, will discuss the convergence of security and network management, organizational barriers to unification, key considerations in implementing security management solutions, and solutions to facilitate integration of security and infrastructure management platforms.

--Deb Curtis, Gartner analyst, will deliver practical guidelines for organizations that are evolving from event management to business service management, highlighting the platforms and processes required to assure maximum business availability and performance.

Additionally, Micromuse executives Lloyd Carney, Micromuse Chairman and CEO, and Dr. Craig Farrell, Micromuse CTO, will deliver keynotes focused on Micromuse's leadership in the assurance space.

About Micromuse

Micromuse Inc. (Nasdaq: MUSE) is the leading provider of ultra-scalable, realtime business and service assurance software solutions. The Netcool(R) software suite provides organizations with the assurance that their IT systems are supporting and driving profits 24 hours a day. Unlike traditional infrastructure management systems, Netcool solutions provide realtime end-to-end visibility and accurate troubleshooting from a business perspective. Such business intelligence allows organizations to respond to problems quickly, streamline workflow processes and improve business uptime. Micromuse customers include BT, Cable & Wireless, Deutsche Telekom, EarthLink, ITC DeltaCom, JPMorgan Chase, MCI, T-Mobile, and Verizon. Headquarters are located at 650 Townsend Street, San Francisco, Calif. 94103; [phone]. The Web site is at www.micromuse.com.

Micromuse and Netcool are registered trademarks of Micromuse Ltd. All other trademarks and registered trademarks in this document are the properties of their respective owners. Any statements contained in this press release that do not describe historical facts may constitute forward-looking statements as that term is defined in the Private Securities Litigation Reform Act of 1995. Any forward-looking statements contained herein are based on current expectations, but are subject to a number of risks and uncertainties.

The factors that could cause actual future results to differ materially from the forward-looking statements include the following: fluctuations in customer demand, the Company's ability to manage its growth (including the ability to hire sufficient sales and technical personnel), the risks associated with the expansion of the Company's distribution channels, the risk of new product introductions and customer acceptance of new products; the rapid technological change which characterizes the Company's markets, the risks associated with competition, the risks associated with international sales as the Company expands its markets, and the ability of the Company to compete successfully in the future, as well as other risks identified in the Company's Securities and Exchange Commission Filings, including but not limited to those appearing under the caption "Risk Factors" in the Company's most recent Quarterly Reports on Form 10-Q and on Form 10-K on file with the Securities and Exchange Commission and available on the Company's Web site.