

	iBasis Ranked New England's Number One Rising Star Among the Region's 50 Fastest-Growing Technology Companies Company Receives Honors for 15,189 % Revenue Growth Since 1997 BURLINGTON, MA-September 14, 2000--iBasis, Inc., (Nasdaq: IBAS), the leader in advanced Internet-based communications, today announced that it has been recognized as the number one Rising Star as part of Deloitte & Touche's elite 2000 "New England Technology Fast 50" program. The Rising Star category ranks New England's fastest-growing technology companies based on three-year revenue growth. With annual revenues that grew 15,189% from 1997 to 1999, iBasis was ranked first among all New England Technology Rising Stars. iBasis is a global leader in providing advanced Internet-based communications services to many of the world's largest telecommunications carriers. iBasis delivers toll quality Internet voice, fax and other converged Internet and telephony services to over 100 international carriers, including 11 of the top 12 US-based international service providers. The company also offers iBasis VoCoreSM, the industry's first hosted Unified Communications solution that enables service providers to quickly and efficiently deliver new, value-added services that integrate email, voicemail, fax, real-time communications and the Web to enhance personal, group and enterprise-wide communication and productivity. "Congratulations to iBasis for being named as our number one Rising Star," said Steve DiPietro, co-chair of the New England Technology Fast 50 Program and partner with Deloitte & Touche. "We will certainly look for iBasis on future Fast 50 lists, as it continues to build on its leadership in Internet-based communications services." "This award recognizes the tremendous growth we have been able to achieve over the past three years as a leader in providing services that unify voice and the Internet," said Ofer Gneezy, president and CEO of iBasis. "New England has become one of the world's great centers of technology and innovation, rivaled only by Silicon Valley. It is a great honor and a special moment for iBasis to be named the number one Rising Star in the prestigious New England Technology Fast 50 program." William Lee, managing partner of Hale and Dorr LLP and co-chair of the program added, "Each year, it becomes more difficult to achieve recognition in the technology field. On behalf of Hale and Dorr, I congratulate iBasis for its innovation and its success, and for joining the prestigious ranks of the Technology Rising Stars." To qualify as a Technology Rising Star, a company must have been in business a minimum of three years, with 1997 operating revenue of at least $50,000 and 1999 operating revenue of at least $1 million. It must be a technology company, strictly defined as one that develops proprietary technology which contributes to a significant portion of the company's operating revenues; manufactures a technology-related product; devotes a high percentage of effort to research and development of technology or uses proprietary technology to significantly improve the delivery of technology services. To qualify for the New England program, the company much also be headquartered in the state of Massachusetts, Rhode Island, New Hampshire, Vermont or Maine. About Deloitte & Touche Deloitte & Touche, one of the nation's leading professional services firms, provides assurance and advisory, tax, and management consulting services through 30,000 people in more than 100 cities. The firm is dedicated to helping its clients and its people excel. Known as an employer of choice for its innovative human resources programs, Deloitte & Touche has been recognized as one of the "100 Best Companies to Work for in America" by Fortune Magazine for three consecutive years. Deloitte & Touche is part of Deloitte Tohmatsu, one of the world's leading professional services firms, with more than 90,000 people in over 130 countries. For more information, please visit Deloitte & Touche's web site at www.us.deloitte.com About Hale and Dorr LLP Hale and Dorr LLP is a nationally preeminent high-technology law firm, with over 400 attorneys and offices in Boston, Washington DC, Reston, VA, and New York. The firm has a strong reputation for advising and guiding emerging growth companies, especially those in the software, telecommunications and biotechnology industries. For more information, visit the firm's web site at www.haledorr.com/ About Mass High Tech Mass High Tech, The Journal of New England Technology is a weekly technology journal serving the executives and management-level engineers of New England's innovation and technology industries. The journal's writers search out innovation and companies working on the "bleeding" edge and then report on their work and its marketplace applications before they make mainstream business news. Most importantly, Mass High Tech profiles and follows the people driving New England's innovation economy. With weekly readership of over 46,000, Mass High Tech's penetration into New England's technology community is unmatched. For more information, visit Mass High Tech online at www.masshightech.com. The iBasis Network Founded in 1996, iBasis (Nasdaq: IBAS) is the leader in advanced Internet-based communications. iBasis has built the world's first global IP network that delivers toll quality voice and fax service and other advanced hosted communications solutions, including Unified Communications, to global tier one carriers and other service providers. The iBasis Network is the world's largest international Cisco Powered Network for Internet Telephony and the first to receive the Unified Communications Cisco Powered Network (UC-CPN) designation. More than 100 international service providers are iBasis customers, including 11 of the top 12 U.S. international carriers. iBasis is listed in both the Russell 2000� and Russell 3000� Indexes. The company can be reached at its worldwide headquarters in Burlington, Mass., 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 iBasis' prospectus dated March 9, 2000, and the company's other SEC filings.