EXHIBIT 5.1



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January 29, 2004

United Parcel Service, Inc.
55 Glenlake Parkway, N.E.
Atlanta, Georgia 30328

         RE: UNITED PARCEL SERVICE, INC. -- REGISTRATION STATEMENT ON FORM S-3

Ladies and Gentlemen:

         We have acted as counsel to United Parcel Service, Inc., a Delaware
corporation (the "Company"), in connection with the preparation of the
Registration Statement on Form S-3 (the "Registration Statement") to be filed
with the Securities and Exchange Commission. The Registration Statement relates
to the offering of up to 30,000,000 shares (the "Company Shares") of the
Company's Class A Common Stock, par value $0.01 per share (the "Common Stock"),
by the Company pursuant to the Company's Class A Common Stock Dividend
Reinvestment Program (the "Plan").

         In connection with this opinion, we have examined and relied upon such
records, documents, certificates and other instruments as in our judgment are
necessary or appropriate to form the basis for the opinions hereinafter set
forth. In all such examinations, we have assumed the genuineness of signatures
on original documents and the conformity to such original documents of all
copies submitted to us as certified, conformed or photographic copies, and as to
certificates of public officials, we have assumed the same to have been properly
given and to be accurate.

         The opinions expressed herein are limited in all respects to the
federal laws of the United States of America and the corporate laws of the State
of Delaware (which includes the Delaware General Corporation Law, applicable
provisions of the Delaware Constitution and reported judicial interpretations
concerning those laws), and no opinion is expressed with respect to the laws of
any other jurisdiction or any effect which such laws may have on the opinions
expressed herein. This opinion is limited to the matters stated herein, and no
opinion is implied or may be inferred beyond the matters expressly stated
herein.

         Based upon the foregoing, and subject to all of the assumptions,
limitations and qualifications set forth herein, we are of the opinion that the
Company Shares have been duly authorized and, when issued in accordance with the
Plan, will be validly issued, fully paid and nonassessable.


United Parcel Service, Inc.
January 29, 2004
Page 2



         This opinion is given as of the date hereof, and we assume no
obligation to advise you after the date hereof of facts or circumstances that
come to our attention or changes in law that occur which could affect the
opinions contained herein. This opinion is being rendered solely for the benefit
of the Company in connection with the matters addressed herein. This opinion may
not be furnished to or relied upon by any person or entity for any purpose
without our prior written consent.

         We consent to the filing of this opinion as an Exhibit to the
Registration Statement and to the reference to us under the caption "Legal
Matters" in the Prospectus that is included in the Registration Statement.

                                                     Very truly yours,



                                                 /s/ KING & SPALDING LLP