iBasis CEO to Present at Kaufman Brothers and Cowen & Company Investor Events

Gneezy will Provide Updates on Company’s Integration of KPN Global Carrier Services and Progress on Acquisition Synergies

BURLINGTON, Massachusetts – 05/20/2008 – iBasis, Inc. (NASDAQ: IBAS), a KPN affiliate, today announced that company President and CEO Ofer Gneezy will present at the Kaufman Brothers Nex-Gen Infrastructure Tech & Services event on Thursday, May 22nd and at the Cowen & Company 20/20 TMT Conference on Thursday, May 29. Both conferences will be held in New York. A copy of the presentation will be posted on May 22nd, and a webcast of the Cowen & Company presentation will be accessible both live and archived on the iBasis investor relations site at investor.ibasis.com.

Mr. Gneezy will provide an update on the company’s successful integration of the KPN Global Carrier Services business it acquired in October 2007, including its achievement of synergies from the transaction with Royal KPN, and discuss the company’s growth strategy for the future.

About the Conferences

The Kaufman Brothers Nex-Gen Infrastructure Tech & Services event will be held May 22, 2008 at the W Hotel, 541 Lexington Avenue, New York. For more information visit the Kaufman Brothers web site at www.kbro.com.

The Cowen & Company 20/20 TMT Conference will be held May 28-30, 2008, at the New York Palace Hotel, 455 Madison Avenue, New York. Cowen conferences are open to Cowen’s institutional clients only. Clients can contact Brian Perry at 617-946-3869 for conference details. A live and archived webcast of Mr. Gneezy’s presentation will be available on the iBasis investor relations site at investor.ibasis.com.

About iBasis

Founded in 1996, iBasis (NASDAQ: IBAS) is a leading wholesale carrier of international long distance telephone calls and a provider of retail prepaid calling services and enhanced services for mobile operators. iBasis customers include KPN, KPN Mobile, E-Plus, BASE, and many other large telecommunications carriers such as Verizon, Vodafone, China Mobile, China Unicom, IDT, Qwest, Skype, Telecom Italia, Telefonica, and Yahoo. In October 2007, iBasis acquired KPN Global Carrier Services to create one of the three largest carriers of international voice traffic in the world, and KPN became a majority stockholder of iBasis. On a pro forma basis, the combined company carried approximately 24 billion minutes of international voice traffic in 2007. The Company can be reached at its worldwide headquarters in Burlington, Mass., USA at +1 781-505-7500 or on the Internet atwww.ibasis.com.