Exhibit 99.1


ProBusiness
                                                           4125 Hopyard Road
                                                           Pleasanton, CA 94588
                                                           (925) 737-3500
Investor Contact:
Steven Klei
Executive Vice President, Finance
Chief Financial Officer
(925) 737-3110

FOR IMMEDIATE RELEASE


             PROBUSINESS TO BE ACQUIRED BY AUTOMATIC DATA PROCESSING
                       FOR $17.00 PER COMMON SHARE IN CASH

PLEASANTON, Calif -- January 6, 2003 -- ProBusiness Services, Inc.
(Nasdaq:PRBZ), a leading provider of outsourced employee administrative services
for large employers providing payroll, payroll tax filing, benefits
administration, Comprehensive Outsourcing, human resources, and Web self-service
solutions, today announced that it will be acquired by Automatic Data
Processing.

ProBusiness has entered into a definitive agreement to be acquired by Automatic
Data Processing for $17.00 per common share, or a total of approximately $500
million, in cash. The transaction is subject to customary closing conditions,
including ProBusiness shareholder approval and normal regulatory review.

"We are excited by the agreement to add ProBusiness' services to ADP's
offerings," said Tom Sinton, ProBusiness CEO. "By combining ProBusiness' focus
on Service Excellence and our leadership in managed services with ADP's
impressive services, global reach and financial strength, we can deliver the
very best solutions to clients, and become a strong contributor to ADP's
continuing success."

ProBusiness will host a conference call at 8:30 a.m. ET / 5:30 a.m. PT today,
Monday, January 6, 2002 to discuss this announcement. Interested parties can
access this conference call by going to the ProBusiness site at
www.probusiness.com and selecting "Special Webcast Announcement" and then
clicking on the webcast icon. ProBusiness encourages you to preview the site to
ensure that your browser is configured properly prior to the call.


ABOUT PROBUSINESS SERVICES, INC.
ProBusiness, Inc. is a provider of HR business process outsourcing (BPO)
services that streamline processes, reduce administrative costs, and improve
service levels for large employers nationwide. ProBusiness offers services in
payroll, payroll tax, benefits administration, human resources, and Web
self-service. Clients have the flexibility to choose either single-function,
stand alone services or multi-function, end-to-end Comprehensive Outsourcing.
Comprehensive Outsourcing extends ProBusiness services with employee-facing
services, such as payroll administration and employee inquiry management,
through employee service centers. Complete information about ProBusiness is
available at http://www.ProBusiness.com.

ABOUT ADP
Automatic Data Processing, Inc. (NYSE:ADP) is one of the largest independent
computing services firms in the world, with $7 billion in revenue and 500,000
clients. ADP Employer Services (ES), a division of ADP, Inc., is a leading
provider of integrated business administrative solutions that help its over
450,000 clients efficiently manage their internal processes, allowing them to
focus on core competencies. ADP's Employer Services offerings include both
traditional and Internet-based outsourcing products and services, giving clients
the ability to select from ADP's comprehensive range of World Class Service
solutions. Services include: payroll, tax regulatory management, HRMS, benefits
administration, time and labor management, retirement plan services, online
recruiting, PEO services, and employment screening and selection.

NOTE TO INVESTORS



ProBusiness Services, Inc. - CONFIDENTIAL



In connection with the merger, ProBusiness will be filing a proxy statement and
other relevant documents concerning the transaction with the Securities and
Exchange Commission (SEC). STOCKHOLDERS OF PROBUSINESS ARE URGED TO READ THE
PROXY STATEMENT AND ANY OTHER RELEVANT DOCUMENTS FILED WITH THE SEC WHEN THEY
BECOME AVAILABLE BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION. Investors and
security holders can obtain free copies of the proxy statement and other
documents when they become available by contacting Investor Relations,
ProBusiness, 4125 Hopyard Road, Pleasanton, CA 94588 (Telephone: (925)
737-3500). In addition, documents filed with the SEC by ProBusiness are
available free of charge at the SEC's web site at www.sec.gov.

Information regarding the identity of the persons who may, under SEC rules, be
deemed to be participants in the solicitation of stockholders of ProBusiness in
connection with the transaction, and their interests in the solicitation, will
be set forth in a proxy statement that will be filed by ProBusiness with the
SEC.

FORWARD-LOOKING STATEMENTS

Except for historical information contained herein, statements contained in this
document may constitute "forward looking statements" within the meaning of the
Private Securities Litigation Reform Act of 1995. These statements are neither
promises nor guarantees, but involve a number of risks, uncertainties and other
factors that could cause actual results to differ materially from those set
forth in the forward-looking statements, including, without limitation, the risk
that the merger may not be consummated, risks regarding employee relations and
other risks concerning ADP and ProBusiness and their respective operations that
are detailed in the periodic filings with the SEC of ADP and ProBusiness,
including their most recent filings on Form 10-K.





ProBusiness Services, Inc. and the ProBusiness logo are registered trademarks of
ProBusiness Services, Inc. All other trademarks and registered trademarks
mentioned herein remain the property of their respective owners.






ProBusiness Services, Inc. - CONFIDENTIAL