SECURITIES AND EXCHANGE COMMISSION
                           Washington, D.C. 20549

                                  FORM 15

       Certification and Notice of Termination of Registration under
          Section 12(g) of the Securities Exchange Act of 1934 or
       Suspension of Duty to File Reports Under Section 13 and 15(d)
                  of the Securities Exchange Act of 1934.

                       Commission File Number 1-5153
                                  -------


                          MARATHON OIL CORPORATION
                    (formerly known as USX Corporation)
                   -------------------------------------
           (Exact name of registrant as specified in its charter)


                            5555 San Felipe Road
                           Houston, TX 77056-2723
                               (713) 629-6600
            (Address, including zip code, and telephone number,
               including area code, of registrant's principal
                             executive offices)

        USX-U.S. Steel Group Common Stock, par value $1.00 per share
(including the associated rights to purchase Series A Junior Preferred Stock)
                6.50% Cumulative Convertible Preferred Stock
               ----------------------------------------------
          (Title of each class of Securities covered by this Form)


         Marathon Oil Corporation Common Stock, par value $1.00 per
        share (Titles of all other classes of securities for which a
         duty to file reports under Section 13(a) or 15(d) remains)


         Please place an X in the box(es) to designate the appropriate rule
         provision(s) relied upon to terminate or suspend the duty to file
         reports:

              Rule 12g-4(a)(1)(i)       [x]     Rule 12h-3(b)(1)(ii)       [  ]
              Rule 12g-4(a)(1)(ii)      [ ]     Rule 12h-3(b)(2)(i)        [  ]
              Rule 12g-4(a)(2)(i)       [ ]     Rule 12h-3(b)(2)(ii)       [  ]
              Rule 12g-4(a)(2)(ii)      [ ]     Rule 15d-6                 [  ]
              Rule 12h-3(b)(1)(i)       [x]

         Approximate number of holders of record as of the certification or
         notice date:  0

         Pursuant to the requirements of the Securities Exchange Act of
         1934, Marathon Oil Corporation has caused this
         certification/notice to be signed on its behalf by the undersigned
         duly authorized person.


         Date:  January 9, 2002                 By:  /s/ JERRY HOWARD
                                                     ------------------------
                                                Name:  Jerry Howard
                                                Title: Senior Vice President
                                                         Corporate Affairs