iBasis Appoints Mary Cogan Vice President of Human Resources

Burlington, Mass.—January 12, 2000—iBasis, Inc., (NASDAQ: IBAS), the leader in international Internet telephony, today announced the appointment of Mary Shanley Cogan as vice president of Human Resources. In this position, Cogan will provide strategic direction for and oversee management of the company's human resources programs and initiatives.

"Mary's proven human resources leadership and extensive background in international recruiting and employee development will significantly enhance our ability to attract and retain the experienced, professional talent we will need to keep pace with our company's rapid growth," said Gordon VanderBrug, executive vice president, iBasis, Inc. . Mary Cogan brings more than a decade of high technology human resource experience to iBasis. Most recently, Cogan was an HR consultant with MSC Associates, a human resource consulting group. In this role, Cogan provided MSC clients senior executive recruiting services, offered consultation on structuring company benefits and compensation packages and designed and helped implement performance management systems. Prior to MSC Associates, Cogan served as the senior director of human resources for Cascade Communications Corp., a global provider of wide area networking products and services for the telecommunications and Internet industries. Her responsibilities at Cascade included global recruiting, developing and implementing all compensation programs and creating a company intranet site to automate key human resource functions. In addition, Cogan has held human resource positions at Summa Four, Inc., Northern Telecom and Data General Corp.

Cogan holds a Master's of Business Administration in Finance and Human Resources from Northeastern University and a Bachelor of Arts degree from the University of Massachusetts.

About iBasis 
Founded in 1996, iBasis (NASDAQ: IBAS) is the global leader in international Internet telephony. iBasis uniquely combines a superior technology platform, premium Internet bandwidth and proprietary Assured Quality Routing™ (AQR) software to deliver toll quality Internet telephony services to tier one carriers and other international service providers. The iBasis Network™, a global, high-capacity Internet communications network, is the world's largest international Cisco Powered Network for Internet Telephony. The company can be reached at its worldwide headquarters in Burlington, Massachusetts, USA at 781-505-7500 or on the Internet at www.ibasis.net.

Except for historical information, all of the expectations, projections and assumptions contained in the foregoing press release 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, the considerations described as "Risk Factors" in the company's prospectus dated November 9, 1999, and the company's other SEC filings.

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iBasis, iBasis Internet Telephony Hosting, The iBasis Network and Assured Quality Routing are registered trademarks of iBasis, Inc.