BURLINGTON, MA. – July 3, 2008 — Acme Packet, Inc. (NASDAQ: APKT), the leader in session border control solutions, today provided a financial update for its second quarter ended June 30, 2008.  The Company expects to release final financial results for the second quarter and any update to its business outlook for fiscal year 2008 on Thursday, August 7, 2008 after the market closes.  Based on preliminary estimates which are subject to change, the Company currently expects:

• Total revenues for the second quarter to be between $24.5 million and $25.5 million;
• Gross margins for the second quarter to be  within the Company’s target range of 77%-79%;
• Net income on a non-GAAP1 basis for the second quarter to be between $1.5 million and $2.5 million, or between $0.02 per share and $0.04 per share on a diluted basis;
• Net income on a GAAP basis for the second quarter to be between $0.2 million and $1.2 million, or between $0.00 per share and $0.02 per share on a diluted basis;
• Non-GAAP1 net income to differ from GAAP net income as it is expected to exclude stock-based compensation expense, net of tax, of approximately $1.3 million, or $0.02 per share;
• Cash and cash equivalents to be approximately $147.0 million, compared to $144.8 million at the end of the first quarter of fiscal 2008; and
• Deferred revenues to increase to between $13.0 million and $14.0 million, compared to $12.8 million at the end of the first quarter of fiscal 2008.

“We are disappointed with our preliminary financial results for the second quarter which are in contrast to the sequential and year-over-year revenue growth we reported in each of the nine preceding quarters,” said Andy Ory, President and Chief Executive Officer of Acme Packet, Inc.  “Our top line results were adversely impacted by two specific factors.  First, there were a number of transactions that unfortunately did not close on the schedule that we had forecasted together with various customers.  We do not believe that any of these opportunities were lost to competitors and we expect these transactions will close in this calendar year.  Second, we shipped a relatively high volume of product in the last several days of the quarter which we were unable to recognize in the second quarter due to time-based acceptance criteria with various customers.  While we are not prepared to comment on our full year outlook at this time, we are clearly targeting a return to sequential revenue growth in the third quarter.  I remain very confident in the long term growth trajectory of the market and our leadership position within it.”

Company to Host Live Conference Call
The Company’s management team will host a live conference call at 8:30 a.m. eastern time today to discuss the preliminary results for the second quarter of fiscal year 2008.  The conference call may be accessed in the United States by dialing (888) 428-4480 and using access code “APKT”.  The conference call may be accessed outside of the United States by dialing (651) 291-0900 and using access code “APKT”.  A replay of the conference call will be available approximately two hours after the call by dialing (800) 475-6701 and using access code 952991.

About Acme Packet,
Acme Packet, Inc. (NASDAQ: APKT), the leader in session border control solutions, enables the delivery of trusted, first class interactive communications—voice, video and multimedia sessions—and data services across IP network borders. Our Net-Net family of session border controllers, multiservice security gateways and session routing proxies supports multiple applications in service provider, large enterprise and contact center networks—from VoIP trunking to hosted enterprise and residential services to fixed-mobile convergence. They satisfy critical security, service assurance and regulatory requirements in wireline, cable and wireless networks; and support multiple protocols—SIP, H.323, MGCP/NCS and H.248—and multiple border points—interconnect, access and data center. Our products have been selected by more than 500 customers in 85 countries, including 29 of the top 30, and 84 of the top 100 service providers in the world. For more information, contact us at +1 781.328.4400, or visit www.acmepacket.com [1].