Exhibit 5.1
   
                        Automatic Data Processing, Inc.
                            Corporate Headquarters
                               One ADP Boulevard
                        Roseland, New Jersey 07068-0456



                                                  August 15, 1996


Board of Directors
Automatic Data Processing, Inc.
One ADP Boulevard
Roseland, NJ  07068

               Re:  Automatic Data Processing, Inc.
                    REGISTRATION STATEMENT ON FORM S-8

Gentlemen:

    I have acted as counsel to Automatic Data Processing, Inc., a Delaware
corporation (the "Company"), in connection with the registration by the Company
of 10,000,000 shares of the Company's Common Stock, par value $.10 per share
(the "Shares"), pursuant to the Company's Registration Statement on Form S-8
which is to be filed with the Securities and Exchange Commission on August 15,
1996 (the "Registration Statement").

    In this connection, I have examined originals or copies, certified or
otherwise identified to my satisfaction, of such corporate records,
certificates and written and oral statements of officers and accountants of the
Company and of public officials, and other documents that I have considered
necessary and appropriate for this opinion and, based thereon, I advise you
that, in my opinion:

 1.  The Company has been duly incorporated and is validly existing under the
 laws of the State of  Delaware.

 2.  The Company has corporate authority to issue the Shares in the manner and
 under the terms set forth in the Registration Statement.

 3.  The Shares have been duly authorized and, when issued in accordance with
 the Company's 1990 Key Employees' Stock Option Plan referred to in the
 Registration Statement, will be validly issued, fully paid and nonassessable.

    I hereby consent to the filing of this opinion as Exhibit 5.1 to the
Registration Statement, to its use part of the Registration Statement, and to
the use of my name in the Registration Statement.

                                 Very truly yours,

                                 /s/ James B. Benson

                                 James B. Benson
                                 General Counsel