8-K

                      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)        September 13, 2002
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                               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.


         On September 13, 2002, Moody's Investors Service, Inc. downgraded to
Baa2 from Baa1 the issuer rating and senior unsecured debt of Unocal Corporation
(the "Company") and of its guaranteed subsidiary, Union Oil Company of
California ("Union Oil"), concluding a review announced on August 22, 2002.
Union Oil's guaranteed Prime-2 commercial paper rating was not under review.
Moody's maintained a stable rating outlook on the Company. The full text of
Moody's news release is filed as an exhibit under Item 7(c) of this report.


Item 7.      Financial Statements and Exhibits

             (c)   Exhibits

             99.1  Moody's   Investors   Service,   Inc.  news  release  dated
                   September 13, 2002.


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
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                                           (Registrant)




Date:  September 18, 2002                  By: /s/ JOHN A. BRIFFETT
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                                           John A. Briffett
                                           Assistant Comptroller


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EX-99

                                                                    Exhibit 99.1

Moody's Investors Service News Release
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Sept 13, 2002
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Moody's downgrades Unocal Corporation long-term debt to Baa2; Pure Resources
confirmed at Baa3 Approximately $5 billion of securities affected.
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    Moody's Investors Service downgraded to Baa2 from Baa1 the issuer rating and
senior unsecured debt of Unocal Corporation and of its guaranteed subsidiary,
Union Oil Company of California, concluding a review announced on August 22,
2002. Union Oil Company's guaranteed Prime-2 commercial paper rating was not
under review. Concurrently, Moody's confirmed the Baa3 senior long-term debt
ratings of Pure Resources Inc. Both entities have a stable rating outlook.
    The rating actions are in response to the expected completion in the
near-term of Unocal's proposed offer to acquire the approximate 35% minority
interest holdings in Pure that it does not already own. The purchase will be
effected through Unocal's issuance of approximately 12 million shares of common
in exchange for the Pure shares. The $400 million of new equity will benefit
Unocal's balance sheet. However, Moody's downgrade of Unocal's long-term ratings
reflects the incremental leverage implication of the $570 million of Pure
Resources debt that will become obligations of a wholly owned, strategic
subsidiary upon completion of the exchange. Previously, Pure's debt obligations
had been issued with no recourse to Unocal.
    In addition, Unocal's financial leverage and cash flow protection measures
were weak within the Baa1 peer group and Unocal's direct debt has increased
approximately $200 million in 2002 as capital spending has exceeded retained
cash flow. Moody's believes that Unocal will have limited opportunities for
substantial leverage reduction over the next few years as it invests heavily to
maintain its reserves and grow production in its key growth areas of the Gulf of
Mexico, Canada, Alaska, Thailand, Indonesia and Azerbaijan.
    The confirmation of Pure Resources' Baa3 senior unsecured debt rating
reflects its status as a wholly-owned subsidiary upon completion of the
exchange. As a separate subsidiary, Pure will have a first call on its own cash
flows to service its debt. However, Unocal does not plan at this time to
guarantee Pure's debt obligations, which will thus be rated one notch below
Unocal's senior unsecured debt.
    The rating actions are taken with the expectation that the exchange offer
will take place largely as planned. If the offer for some reason were not
completed, Moody's would re-evaluate the Baa3 rating of Pure Resources but would
not be likely to review or change Unocal's ratings.
    Securities downgraded include:
    Unocal Corporation issuer rating, bank loan ratings and debentures to Baa2
from Baa1; its capital trust preferred stock to Baa3 from Baa2;
    Union Oil Company of California's guaranteed debentures, senior notes,
medium-term notes, bank loan ratings, industrial revenue bonds, and issuer
rating.
    Securities confirmed are the Baa3 senior notes of Pure Resources, Inc.
    Unocal  Corporation is  headquartered  in El Segundo,  California.
Pure Resources,  Inc. is  headquartered  in Midland, Texas.

ALL INFORMATION CONTAINED HEREIN IS COPYRIGHTED IN THE NAME OF MOODY'S INVESTORS
SERVICE,  INC.  ("MOODY'S"),  AND  NONE OF SUCH  INFORMATION  MAY BE  COPIED  OR
OTHERWISE   REPRODUCED,    REPACKAGED,    FURTHER   TRANSMITTED,    TRANSFERRED,
DISSEMINATED, REDISTRIBUTED OR RESOLD, OR STORED FOR SUBSEQUENT USE FOR ANY SUCH
PURPOSE,  IN WHOLE OR IN PART, IN ANY FORM OR MANNER OR BY ANY MEANS WHATSOEVER,
BY ANY PERSON WITHOUT MOODY'S PRIOR WRITTEN CONSENT.  All information  contained
herein is obtained by MOODY'S  from  sources  believed by it to be accurate  and
reliable.  Because of the  possibility of human and mechanical  error as well as
other factors, however, such information is provided "as is" without warranty of
any kind and  MOODY'S,  in  particular,  makes no  representation  or  warranty,
express   or   implied,   as  to   the   accuracy,   timeliness,   completeness,
merchantability  or fitness for any particular  purpose of any such information.
Under no  circumstance  shall MOODY'S have any liability to any person or entity
for (a) any loss or damage in whole or in part  caused by,  resulting  from,  or
relating  to any  error  (negligent  or  otherwise)  or  other  circumstance  or
contingency  within or outside the  control of MOODY'S or any of its  directors,
officers,  employees or agents in connection with the  procurement,  collection,
compilation, interpretation,  communication, publication or delivery of any such
information, or (b) any direct, indirect, special, consequential, compensatory

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or incidental damages whatsoever  (including without limitation,  lost profits),
even if  MOODY'S is advised  in  advance  of the  possibility  of such  damages,
resulting from the use of, or inability to use, any such information. The credit
ratings, if any,  constituting part of the information contained herein are, and
must be construed solely as, statements of opinion and not statements of fact or
recommendations to purchase, sell or hold any securities.  NO WARRANTY,  EXPRESS
OR IMPLIED,  AS TO THE ACCURACY,  TIMELINESS,  COMPLETENESS,  MERCHANTABILITY OR
FITNESS  FOR ANY  PARTICULAR  PURPOSE  OF ANY SUCH  RATING OR OTHER  OPINION  OR
INFORMATION IS GIVEN OR MADE BY MOODY'S IN ANY FORM OR MANNER  WHATSOEVER.  Each
rating or other opinion must be weighed  solely as one factor in any  investment
decision made by or on behalf of any user of the information  contained  herein,
and each such user must  accordingly  make its own study and  evaluation of each
security  and of each  issuer  and  guarantor  of, and each  provider  of credit
support for, each security that it may consider purchasing,  holding or selling.
Pursuant  to  Section  17(b)  of the  Securities  Act of  1933,  MOODY'S  hereby
discloses  that  most  issuers  of  debt  securities  (including  corporate  and
municipal  bonds,  debentures,  notes and commercial  paper) and preferred stock
rated by MOODY'S have, prior to assignment of any rating,  agreed to pay MOODY'S
for the appraisal and rating services rendered by it fees ranging from $1,000 to
$1,500,000.

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