SECURITIES AND EXCHANGE COMMISSION
                              Washington, DC 20549



                                    FORM 8-K



                             Current Report Pursuant
                          to Section 13 or 15(d) of the
                         Securities Exchange Act of 1934



    Date of report (Date of earliest event reported)        April 1, 2003
                                                        ------------------------



                               UNOCAL CORPORATION
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             (Exact name of registrant as specified in its charter)



                                    Delaware
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                 (State or Other Jurisdiction of Incorporation)



    1-8483                                   95-3825062
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(Commission File Number)                (I.R.S. Employer Identification No.)



2141 Rosecrans Avenue, Suite 4000, El Segundo, California         90245
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(Address of Principal Executive Offices)                       (Zip Code)



                                 (310) 726-7600
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              (Registrant's Telephone Number, Including Area Code)



Item 5.      Other Events.

The Rights Agreement, dated as of January 5, 2000, between Unocal Corporation,
and Mellon Investor Services LLC, as rights agent, has been amended effective
April 1, 2003. The amendment is filed as an exhibit under Item 7(c) of this
report.


Item 7.  Financial Statements and Exhibits.

(c)      Exhibits

         10.  Amendment to Rights Agreement, dated as of April 1, 2003, between
              Unocal Corporation and Mellon Investor Services LLC.





Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned, thereunto duly authorized.




                                                 UNOCAL CORPORATION
                                                   (Registrant)




Date:  April 2, 2003                        By:  /s/ JOE D. CECIL
      ------------------                         -------------------------------
                                                 Joe D. Cecil
                                                 Vice President and Comptroller

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