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)        December 29, 2004
                                                        ------------------------



                               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)

Check the appropriate box below if the Form 8-K filing is intended to
simultaneously satisfy the filing obligation of the registrant under any of the
following provisions:

|_| Written communications pursuant to Rule 425 under the Securities Act
|_| Soliciting material pursuant to Rule 14a-12 under the Exchange Act
|_| Pre-commencement communications pursuant to Rule 14d-2(b) under the
    Exchange Act
|_| Pre-commencement communications pursuant to Rule 13e-4(c) under the
    Exchange Act



Item 1.01.      Entry into a Material Definitive Agreement.
Item 5.02(b).   Departure of Principal Officer.
Item 5.02(c).   Appointment of Principal Officer.

On December 29, 2004, Mr. Joe D. Cecil, Vice President and Comptroller,
announced his decision to retire from Unocal Corporation ("Unocal") and its
wholly-owned subsidiary, Union Oil Company of California ("Union Oil"),
effective April 1, 2005. Mr. Cecil has served the company in various capacities
for over 33 years. In consideration of Mr. Cecil's continued services to Unocal
and Union Oil during a transition period through March 31, 2005 and his
availability thereafter through March 31, 2006 to respond to any company
inquiries, Union Oil and Mr. Cecil entered into a retention payment agreement
(attached to this report as Exhibit 10.1) on December 29, 2004, whereby Mr.
Cecil is entitled to a retention payment on April 1, 2005 pursuant to the terms
and conditions of the agreement.

Mr. John A. Briffett, currently Assistant Comptroller of Unocal and Union Oil,
is expected to assume the position of Vice President and Comptroller of Unocal
and Union Oil, effective April 1, 2005. Mr. Briffett, age 58, has served in a
variety of finance and accounting positions since joining the company in 1969.
In 1995, he became Assistant Comptroller. In 1996, he became Assistant to the
President. In 1997, he became Assistant Treasurer. In 1998, he resumed his
current position as Assistant Comptroller. Mr. Briffett has not entered into any
employment agreement in connection with his appointment as Vice President and
Comptroller.

Item 9.01  Financial Statements & Exhibits.

(c)  Exhibit 10.1 - Retention Payment Agreement,  dated as of December 29, 2004,
     by and between Union Oil Company of California and Mr. Joe D. Cecil.

                                    Signature

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 hereunto duly authorized.


                                              UNOCAL CORPORATION
                                                 (Registrant)




Date:  December 30, 2004                      By:  /s/ Terry G. Dallas
                                              -------------------------------
                                              Terry G. Dallas
                                              Executive Vice President and
                                              Chief Financial Officer

                                      -1-

EX-10

                                                                    Exhibit 10.1

                          Retention Payment Agreement
                          ---------------------------

This Retention Payment Agreement (hereafter referred to as "Agreement"), is by
and between Mr. Joe D. Cecil (hereafter referred to as "Employee"), and Union
Oil Company of California (hereafter referred to as "Company").

In consideration of the mutual promises contained in this Agreement, the receipt
and sufficiency of which are hereby acknowledged, Company and Employee agree as
follows:

                                    Section 1

Employee must satisfy all of the following conditions in order to receive the
Retention Payment:

     1.   Employee  remains an  Employee of the  Company  through and  including
          March 31, 2005; and

     2.   Employee performs all of Employee's  assigned job  responsibilities in
          at least a satisfactory manner, in the sole good-faith judgment of the
          Management Committee; and

     3.   Employee  complies with all  applicable  Company  policies in the sole
          good-faith judgment of the Management Committee.

     4.   Employee's  employment with the Company voluntarily  terminates at the
          convenience of the company by early retirement on April 1, 2005.

                                    Section 2

If the Employee becomes eligible for a Retention Payment, the amount of the
Retention Payment shall be Two Hundred eighty-five Thousand United States
Dollars and No Cents ($285,000.00), less applicable taxes and other withholding
required by law.

The Retention Payment shall be paid in a single sum on April 1, 2005.

The Retention Payment shall not increase Employee's benefits under any other
benefit plan or compensation program of the Company, including, without
limitation, the Unocal Retirement Plan, the Unocal Savings Plan, the Unocal
Annual Incentive Program, the Unocal Incentive Compensation Plan, Stock Options,
Performance Shares, or Restricted Stock. Further, the Retention Payment shall
not be eligible for deferral into the Unocal Deferred Compensation Plan unless
the Unocal Deferred Compensation Plan is amended to allow the inclusion of
Retention Payments prior to payment of the Retention Payment.

                                    Section 3

For the time period beginning April 1, 2005 through and including March 31,
2006, Employee will be reasonably available to answer questions from the Company
or the Company's representatives via telephone and e-mail. Company and Employee
anticipate that the amount of time per month will be 15 hours, more or less.
However, in the event of a an inquiry regarding calendar year 2004, the number
of telephone and email hours noted above may be substantially exceeded and
employee shall also be reasonably available from time to time to come to the
company office in El Segundo, California to assist regarding responses to such
inquiry. Even if such additional services are needed, Employee shall not receive
any compensation in addition to the Retention Payment for providing such
services except for the reasonable documented expenses incurred in the
performance of such services for the company in accordance with the company's
expense account policy. Employee shall not be reimbursed for commuting expenses
from home to the El Segundo office.

                                    Section 4

This Agreement is a full and complete expression of the intent of the parties
with respect to the subject matter of this Agreement. No other agreement or
representation, express or implied, has been made by either party with respect
to the subject matter of this Agreement.

                                      -1-


                                    Section 5

This Agreement does not modify the provisions of any other written agreement
between an authorized representative of Company and Employee.

                                    Section 6

This Agreement may not be modified except by a written agreement signed by
Employee and by Company's Chief Financial Officer.

                                    Section 7

This Agreement shall be governed by the laws of the state of California
(excluding California' choice of law rules), shall be interpreted to be valid to
the full extent possible under California law and shall not be construed against
any party.

IN WITNESS WHEREOF, this Retention Payment Agreement has been signed in
duplicate originals.


UNION OIL COMPANY OF CALIFORNIA     (Company)

Signature:  /s/ Terry G. Dallas
            -------------------
Print Name: Terry G. Dallas
Title:  Executive Vice President & Chief Financial Officer
Date:   December 29, 2004


JOE D. CECIL (Employee)

Signature:  /s/ Joe D. Cecil
            ----------------
Print Name: Joe D. Cecil
Title:  Vice President & Comptroller
Date:   December 29, 2004

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