EXHIBIT 99.1
                                                                    ------------


           ADP COMPLETES ITS ACQUISITION OF PROBUSINESS SERVICES, INC.


         ROSELAND, New Jersey -- June 20, 2003 -- Arthur F. Weinbach, chairman
and chief executive officer of Automatic Data Processing, Inc. (NYSE: ADP),
announced that ADP closed its acquisition of ProBusiness Services, Inc. (NASDAQ:
PRBZ) today for $17.00 per common share, or a total of approximately $500
million, in cash, following the early termination of the Hart-Scott-Rodino
waiting period.

         ProBusiness, located in Pleasanton, California, with revenues of
approximately $170 million, is a leading provider of comprehensive payroll and
human resource processing solutions to large employers in the United States.

         ADP, with $7 billion in revenues and over 500,000 clients, is one of
the largest independent computing services firms in the world.

         This release and other written or oral statements made from time to
time by ADP may contain "forward-looking statements" within the meaning of the
Private Securities Litigation Reform Act of 1995. Statements that are not
historical in nature and which may be identified by the use of words like
"expects," "projects," "anticipates," "estimates", "we believe", "could be" and
other words of similar meaning, are forward-looking statements. These statements
are based on management's expectations and assumptions and are subject to risks
and uncertainties that may cause actual results to differ materially from those
expressed. Factors that could cause actual results to differ materially from
those contemplated by the forward-looking statements include: ADP's success in
obtaining, retaining and selling additional services to clients; the pricing of
products and services; changes in laws regulating payroll taxes, professional
employer organizations and employee benefits; overall market and economic
conditions, including interest rate and foreign currency trends; competitive
conditions; stock market activity; auto sales and related industry changes;
employment and wage levels; changes in technology; availability of skilled
technical associates and the impact of new acquisitions and divestitures. ADP
disclaims any obligation to update any forward-looking statements, whether as a
result of new information, future events or otherwise.

         The information and opinions contained in this release have been
furnished and approved by Automatic Data Processing, Inc. We are retained by
them as investor relations counsel.


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