iBasis CEO at Mass. Telecom Council Investor Conference: iBasis Has Taken Lead in International VoIP

Record Traffic - More than 28 Million Minutes over Mother's Day Weekend - Other Metrics Show How iBasis Has Ascended to Top Spot in International VoIP Market

BURLINGTON, MASS. - May 13, 2003 - iBasis, Inc. (OTCBB: IBAS), the leader in Internet-based voice communications, today announced that company President and CEO Ofer Gneezy will discuss research findings and financial metrics that indicate that iBasis has overtaken its major rival to become the leading international voice over IP (VoIP) carrier. Mr. Gneezy will be presenting at the Massachusetts Telecom Council's annual Investor Conference in Boston on Thursday, May 15.

In his remarks, Mr. Gneezy will highlight several fundamental factors that differentiate iBasis from traditional telecommunications carriers and other wholesale international carriers. Mr. Gneezy will also discuss the characteristics that position VoIP as the preferred network technology and iBasis as the preferred international wholesale carrier in the new telecommunications industry that is emerging from the turmoil of the last two years.

iBasis recently achieved company traffic records for highest volume weekend and highest volume single day with more than 28 million minutes carried over the past weekend, including more than 15 million minutes on Mother's Day, an increase of 65% over Mother's Day 2002.

"Wholesale international VoIP is a growing market that is led by two major carriers followed by many smaller players," said Gneezy. "Over the last two years iBasis has clearly been the industry leader in customer satisfaction, as demonstrated by our top ranking in the Atlantic ACM Wholesale Carriers Report Card for both 2001 and 2002. With five consecutive quarters of improving gross margins and reducing expenses, we have demonstrated the superior efficiency of our business model as well."

About the Massachusetts Telecom Council Investor Conference

The Massachusetts Telecommunications Council's Tenth Annual MTC Investors Conference on May 15, 2003 at the Westin Copley Place in Boston is one of the region's key technology events and provides a unique forum for investors, analysts, industry decision-makers and the media to get current information about a select group of the Commonwealth's top telecommunications companies. Presentations are made throughout the day by CEOs and CFOs from 40 early stage and mid- to late-stage private telecommunications companies as well as public companies such as iBasis. For a complete listing of participating companies and registration information, visit the MTC website at www.masstel.org.

About iBasis

Founded in 1996, iBasis (OTCBB: IBAS) is a leading provider of wholesale international telecommunications services. Named each of the last two years by service providers as the #1 international wholesale carrier in Atlantic-ACM's annual International Wholesale Carrier Report Card, iBasis is a preferred provider for many of the largest carriers in the world. Customers include AT&T, Cable & Wireless, China Mobile, China Unicom, Sprint, Telefonica, Telenor, Telstra, and WorldCom. The company's global VoIP infrastructure, The iBasis NetworkTM, is the world's largest international Cisco Powered NetworkTM for Internet Telephony. Based on its revenue growth from 1997 through 2001, iBasis was ranked the #8 fastest-growing technology company in North America and the #1 fastest-growing technology company in New England in the Technology Fast 500 national program sponsored by Deloitte & Touche. The company can be reached at its worldwide headquarters in Burlington, Massachusetts, USA at 781-505-7500 or on the Internet at www.ibasis.com.

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Assured Quality Routing, iBasis, and ConnectPoint are registered marks, The iBasis Network, Internet Central Office, Internet Branch Office, and IP CallCard are trademarks of iBasis, Inc. Cisco and Cisco Powered Network are registered trademarks of Cisco Systems, Inc. All other trademarks are the property of their respective owners.

Except for historical information, all of the expectations, projections and assumptions contained in the foregoing press release, including those relating to the company's current expectations regarding revenue growth, sources of revenue, margin improvement and future capital expenditures constitute forward-looking statements under the Private Securities Litigation Reform Act of 1995 and involve risks and uncertainties. Important factors that could cause actual results to differ materially from such forward-looking statements include, but are not limited to, (i) the extent of adoption of the company's services and the timing and amount of revenue generated by these services; (ii) fluctuations in the market for and pricing of these services; and (iii) the other considerations described as "Risk Factors" in iBasis' most recent Forms 10-K and 10-Q, and the company's other SEC filings. We have no current intention to update any forward-looking statements.