NEW BRUNSWICK, New Jersey, May 22 /PRNewswire/ --

- Company offers increased opportunities for efficiency and growth
through thexchange

Arbinet-thexchange, Inc. (Nasdaq: ARBX), the robust transaction platform
for buying and selling voice and IP telecommunications capacity, announced
today that it has surpassed the 1,000 Member mark during the first quarter of
2008. The company also indicated that March 2008 was the highest revenue
month since its inception.

Arbinet, which now has 1,045 Members on the thexchange, experienced an
increase in Membership due to the company's expansion in many emerging
markets. Recently Arbinet announced its increased presence in the Middle East
market, signing on a number of new customers and opening an office in Beirut
to handle the demands of service providers in the region. In addition, the
company has experienced membership growth in Asia, Africa and Latin America.

"Arbinet's increased membership base and continuous global expansion
enable us to offer more choices and greater connectivity," said William
Freeman, president and CEO, Arbinet. "Our solutions, coupled with our
intelligent platform and routing expertise, empower Members to manage their
operations and grow their businesses more effectively."

As Arbinet expands its presence globally, the company continues to
attract buyers and sellers to its marketplace with a range of services that
enhance business choices and opportunities for its Members. Arbinet's
flexible, scalable solutions and managed services enable telecommunications
providers to improve business efficiency and excel in an increasingly
demanding and competitive market. This 1,000 Member milestone is a result of
the outstanding solutions and services Arbinet continues to provide to
Members around the world.

About Arbinet

Arbinet is a leading provider of innovative voice and IP solutions
empowering communications companies to create the most efficient and valuable
global interconnections. Arbinet offers the greatest flexibility in global
scale, platform intelligence, and managed solutions to achieve commercial
efficiency and interconnection simplicity.

Arbinet manages business relationships, back office operations and call
routing for Members who route through Arbinet approximately 2% of the world's
international voice traffic to over 1,300 destinations worldwide. These
Members include fixed line, mobile, wholesale and VoIP carriers as well as
calling card, ISPs and content providers around the world who buy and sell
voice and IP telecommunications capacity and content. For more information
about Arbinet's solutions, visit www.arbinet.com

Forward-Looking Statements

This press release contains forward-looking statements regarding
anticipated future revenues, growth, capital expenditures, management's
future expansion plans, expected product and service developments or
enhancements, and future operating results. Such forward-looking statements
may be identified by, among other things, the use of forward-looking
terminology such as: "believes," "expects," "may," "will," "should" or
"anticipates," or the negative thereof or other variations thereon or
comparable terminology, or by discussions of strategy that involve risks and
uncertainties. Various important risks and uncertainties may cause Arbinet's
actual results to differ materially from the results indicated by these
forward-looking statements, including, without limitation: the ability of
Arbinet to effectively divest Broad Street Digital Limited; members (in
particular, significant trading members) not trading on our exchange or
utilizing our new and additional services (including DirectAxcess(SM),
PrivateExchange(SM), AssuredAxcess(SM) and PeeringSolutions(SM)); continued
volatility in the volume and mix of trading activity; our uncertain and long
member enrollment cycle; the failure to manage our credit risk; failure to
manage our growth; pricing pressure; investment in our management team and
investments in our personnel; regulatory uncertainty; system failures, human
error and security breaches that could cause Arbinet to lose members and
expose it to liability; and Arbinet's ability to obtain and enforce patent
protection for our methods and technologies. For a further list and
description of the risks and uncertainties the Company faces, please refer to
Part I, Item 1A of the Company's Annual Report on Form 10-K, filed with the
Securities and Exchange Commission on March 17, 2008, and other filings that
have been filed with the Securities and Exchange Commission. Arbinet assumes
no obligation to update any forward-looking statements, whether as a result
of new information, future events or otherwise and such statements are
current only as of the date they are made.

Kristen Massaro
    STC Associates
    +1-212-725-1900 ext. 204
    kristen@stcassociates.com

    Mark Brugger
    Arbinet-thexchange, Inc.
    +1-732-509-9160
    mdbrugger@arbinet.com

Web site: http://www.arbinet.com