FORM 3

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person *   BRIFFETT JOHN A 2. Date of Event Requiring Statement (Month/Day/Year) 04/01/2005 3. Issuer Name and Ticker or Trading Symbol UNOCAL CORP [UCL] (Last) (First) (Middle) C/O UNOCAL CORPORATION,, 2141 ROSECRANS AVENUE, SUITE 4000 4. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) Vice President and Comptroller 5. If Amendment, Date Original Filed(Month/Day/Year) (Street) EL SEGUNDO, CA 90245 6. Individual or Joint/Group Filing(Check Applicable Line) _X_ Form filed by One Reporting Person ___ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Beneficially Owned

1.Title of Security (Instr. 4) 2. Amount of Securities Beneficially Owned (Instr. 4) 3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5) 4. Nature of Indirect Beneficial Ownership (Instr. 5) Common Stock / $1.00 Par Value (1) 8,648 D   Common Stock / $1.00 Par Value (1) 6,083.882 I Unocal Savings Plan (401-K)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.			SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 4)	2. Date Exercisable and Expiration Date (Month/Day/Year)		3. Title and Amount of Securities Underlying Derivative Security (Instr. 4)		4. Conversion or Exercise Price of Derivative Security	5. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Option / (Right to Buy)	08/12/2001(2)	02/12/2011	Common Stock / $1.00 Par Value (1)	5,599	$ 36.26	D	Â
Option / (Right to Buy)	08/12/2002(3)	02/12/2012	Common Stock / $1.00 Par Value (1)	3,280	$ 34.725	D	Â
Option / (Right to Buy)	08/11/2003(4)	02/11/2013	Common Stock / $1.00 Par Value (1)	4,322	$ 27.07	D	Â
Option / (Right to Buy)	02/10/2005(5)	02/10/2014	Common Stock / $1.00 Par Value (1)	5,154	$ 36.869	D	Â
Option / (Right to Buy)	02/08/2006(6)	02/08/2015	Common Stock / $1.00 Par Value (1)	4,583	$ 49.305	D	Â

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
BRIFFETT JOHN A C/O UNOCAL CORPORATION, 2141 ROSECRANS AVENUE, SUITE 4000 EL SEGUNDO, CA 90245	Â	Â	  Vice President and Comptroller	Â

Signatures

Paul R Moore, Asst Secretary, Attorney-In-Fact		04/08/2005
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 5(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	Common Stock has attached Preferred Stock Purchase Rights. If and when the Rights become exercisable, the holders would initially be entitled to purchase one one-hundredth of a share of Series B Junior Participating Preferred stock at a purchase price determined pursuant to the Rights Agreement.
(2)	The option becomes exercisable in four equal installments on 8/12/01, 02/12/02, 02/12/03, and 02/12/04
(3)	The option becomes exercisable in four equal installments on 8/12/2002, 2/12/2003, 2/12/2004 and 2/12/2005.
(4)	The option becomes exercisable in four equal installments on 8/11/2003; 2/11/2004; 2/11/2005; and 2/11/2006
(5)	The stock option becomes exercisable in three equal annual installments on 2-10-2005, 2-10-2006 and 2-10-2007.
(6)	The option becomes exercisable in three equal installments on 2/8/2006, 2/8/2007 and 2/8/2008.
  Remarks: Note: Also see attached Exhibit EX-24 Power of Attorney.

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