WESTFORD, MA, February 10, 2009 – Sonus Networks, Inc. (Nasdaq: SONS), a market leader in IP communications infrastructure, today announced that it will release financial results for the fourth quarter and full year 2008 prior to opening of the market on Thursday, February 26th 2009, and will host a conference call with financial analysts and investors at 10:00am ET that day.

To listen via telephone:

Dial-in number: 800-891-3448
International Callers: +1 212-231-2902

To listen via the Internet:

Sonus will host a live webcast of the conference call. To access the webcast, visit www.sonusnet.com, Corporate, Investor Relations.

Replay:

A telephone playback of the call will be available following the conference and can be accessed by calling 800-633-8284 or for international callers, please call +1 402-977-9140. The reservation number for the telephone playback is 21414833, and will be available until March 12, 2009.

A replay of the webcast will be also available on the Sonus Networks Investor Relations website. To access the replay of the webcast, visit www.sonusnet.com, Corporate, Investor Relations.

About Sonus Networks

Sonus Networks, Inc. is a market leader in IP communications infrastructure for wireline and wireless service providers.  With its comprehensive IP Multimedia Subsystem (IMS) solution, Sonus addresses the full range of carrier applications, including residential and business voice services, wireless voice and multimedia, trunking and tandem switching, carrier interconnection and enhanced services.  Sonus' voice infrastructure solutions are deployed in service provider networks worldwide.  Founded in 1997, Sonus is headquartered in Westford, Massachusetts.  Additional information on Sonus is available at http://www.sonusnet.com.

This release may contain forward-looking statements regarding future events that involve risks and uncertainties. Readers are cautioned that these forward-looking statements are only predictions and may differ materially from actual future events or results. Readers are referred to Item 1A “Risk Factors” of our Annual Report on Form 10-K for the year ended December 31, 2007 and all subsequent Quarterly Reports on Form 10-Q, which identify important risk factors that could cause actual results to differ from those contained in the forward-looking statements. Risk factors include among others: the Company’s ability to align its cost structure with market conditions, the impact of material weaknesses in our disclosure controls and procedures and our internal control over financial reporting on our ability to report our financial results timely and accurately; the unpredictability of our quarterly financial results; risks and uncertainties associated with the Company’s restatement of its historical stock option granting practices and accounting including regulatory actions; actions that may be taken by significant shareholders; risks associated with our international expansion; and the impact the current global financial market conditions may have on the telecommunications industry. Any forward-looking statements represent Sonus’ views only as of today and should not be relied upon as representing Sonus’ views as of any subsequent date. While Sonus may elect to update forward-looking statements at some point, Sonus specifically disclaims any obligation to do so, except as required by law.

Sonus is a registered trademark of Sonus Networks, Inc. All other company and product names may be trademarks of the respective companies with which they are associated.

For more information, please contact:

Investor Relations:
David Roy / Karin Cellupica
978-614-8253 / 978-614-8615
droy@sonusnet.com
kcellupica@sonusnet.com

Media Relations:
Lucy Millington
978-614-8240
lmillington@sonusnet.com