Filed by USX Corporation
                           Pursuant to Rule 425 under the Securities Act of 1933
                                        And deemed filed pursuant to Rule 14a-12
                                          Of the Securities Exchange Act of 1934
                                               Subject Company:  USX Corporation
                                                      Commission File No. 1-5153


          PITTSBURGH, July 31 - Thomas J. Usher, chairman and CEO of USX
Corporation (NYSE: X, MRO), today announced that, based in part on the advice of
Credit Suisse First Boston and Salomon Smith Barney,  the USX board of directors
has approved a definitive plan of reorganization, which envisions a tax-free
spin-off of the steel and steel-related business of USX into a publicly traded
company to be called United States Steel Corporation and the remaining energy
business of USX to operate as Marathon Oil Corporation.
          Usher also announced that the USX board has identified the directors
for Marathon Oil Corporation and United States Steel Corporation, who will begin
board service following completion of the planned reorganization.
          The current USX board will continue to oversee the affairs of the
corporation until the reorganization is completed.
          Current USX directors who will serve on the new board of Marathon Oil
Corporation include Usher (chairman), Clarence P. Cazalot, Jr. (president &
CEO), Dr. Shirley Ann Jackson, Charles R. Lee, Douglas C. Yearly, Seth E.
Schofield, Charles A. Corry and Neil A. Armstrong.
          Joining the Marathon Oil Corporation board will be David A. Daberko,
chairman and chief executive officer of National City Corporation and Dennis H.
Reilley, chairman, president and chief executive officer of Praxair, Inc.
          Current USX directors who will serve on the new board of United States
Steel Corporation include Usher (chairman, president & CEO), Dr. Shirley Ann
Jackson, Charles R. Lee, Douglas C. Yearly, Seth E. Schofield, Paul E. Lego,
John F. McGillicuddy, J. Gary Cooper and John W. Snow.
          Joining the United States Steel board will be Robert J. Darnall,
chairman of Prime Advantage Corporation and former chairman and CEO of Inland
Steel Industries.
           Usher emphasized that the planned reorganization is subject to
approval of USX shareholders, receipt of a favorable tax ruling from the
Internal Revenue Service (IRS) on the tax-free nature of the transaction,
completion of necessary financing arrangements and receipt of necessary
regulatory and third party consents.  The transaction is expected to occur at
year-end, subject to the absence of any materially adverse change in business
conditions for the energy and/or steel business, delay in obtaining the IRS
ruling or other unfavorable circumstances.

                                    * * * * *

          The foregoing contains "forward-looking statements" which are based on
(1) a number of assumptions concerning future events made by management and (2)
information currently available to management.  Readers are cautioned not to put
undue reliance on such forward-looking statements, which are not a guarantee of
performance and are subject to a number of uncertainties and other facts, many
of which are outside USX Corporation's control, that could cause actual events
to differ materially from such statements.  For a more detailed description of
the factors that could cause such a difference, please see USX Corporation's
filings with the Securities and Exchange Commission.  There are also a number of
uncertainties, risks, conditions and other factors which could prevent the
implementation of the above described plan of reorganization.
          In connection with the above described transactions, USX Corporation
intends to file a proxy statement and other materials with the Securities and
Exchange Commission.  Security holders are urged to read these materials when
they become final because they will contain important information.  Investors
and security holders may obtain a free copy of these materials as well as other
materials filed with the Securities and Exchange Commission concerning USX
Corporation at the Securities and Exchange Commission's website at  In addition, these materials and other documents may be
obtained for free from USX Corporation by directing a request to USX Corporation
at 600 Grant Street, Pittsburgh, PA  15219; Attn:  Investor Relations.
          USX Corporation and its officers and directors may be deemed to be
participants in the solicitation of proxies from USX Corporation's stockholders
with respect to these transactions.  Information regarding such officers and
directors is included in USX Corporation's proxy statement for its 2001 annual
meeting of stockholders filed with the Securities and Exchange Commission on
March 12, 2001.  This document is available free of charge at the SEC's internet
site or from USX Corporation as described above.