SCHEDULE 14A INFORMATION

          Proxy Statement Pursuant to Section 14(a) of the Securities
                    Exchange Act of 1934 (Amendment No.  )
        
Filed by the Registrant [X]

Filed by a Party other than the Registrant [_] 

Check the appropriate box:

[_]  Preliminary Proxy Statement         [_]  Confidential, for Use of the
                                              Commission Only (as permitted by
                                              Rule 14a-6(e)(2))

[_]  Definitive Proxy Statement 

[X]  Definitive Additional Materials 

[_]  Soliciting Material Pursuant to Section 240.14a-11(c) or Section 240.14a-12

                          Atlantic Richfield Company
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               (Name of Registrant as Specified In Its Charter)


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   (Name of Person(s) Filing Proxy Statement, if other than the Registrant)

   
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         pursuant to Exchange Act Rule 0-11 (Set forth the amount on which
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Notes:




 
[ARCO LOGO APPEARS HERE]      333 South Hope Street
                              Los Angeles, California 90071
                              Telephone 213 486 1774
 
                              BRUCE G. WHITMORE
                              Senior Vice President,
                              General Counsel & Secretary
 
 
                                          April 13, 1999
 
Dear Stockholder:
 
   I am sure that you have recently heard the news about the Merger Agreement
that ARCO signed with BP Amoco. As a result of the proposed merger and the need
for ARCO stockholder approval, there may be some confusion about our upcoming
Annual Stockholders Meeting on May 3, 1999.
 
   ARCO's stockholders will NOT be asked to consider or vote on the proposed
merger at the Annual Meeting. FOR LEGAL REASONS WE WILL NOT DISCUSS, OR ANSWER
QUESTIONS ABOUT, THE PROPOSED MERGER AT THIS MAY 3RD MEETING. The Annual
Meeting will be limited to the official business described in the Proxy
Statement previously mailed to you -- the election of directors, approval of
the appointment of auditors and consideration of a stockholder proposal. We
still need your votes on these matters and encourage you to send in your
proxies. However, we expect the meeting to be fairly brief.
 
   ARCO is preparing a proxy statement for distribution to you describing the
proposed merger. Once the merger proxy statement has been completed, approved
by the SEC and mailed, we will hold a Special Stockholders Meeting to consider
the merger. That meeting will probably occur in a few months.
 
   I am sorry that we will not be able to have a full discussion about the
proposed merger at this time. Thank you for your patience during this period of
transition.
 
                                          Sincerely yours,
 

                                          /s/ Bruce G. Whitmore
 
 


Atlantic Richfield Company