Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN 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
OMB APPROVAL
OMB Number: 3235-0287
Expires: January 31, 2005
Estimated average burden hours per response... 0.5

(Print or Type Responses)
1. Name and Address of Reporting Person *
PLAGA BARRY J
   2. Issuer Name and Ticker or Trading Symbol
SUN MICROSYSTEMS, INC. [SUNW] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
VP & Corporate Controller
(Last)
(First)
(Middle)
4150 NETWORK CIRCLE		 3. Date of Earliest Transaction (Month/Day/Year)
01/31/2006
(Street)

SANTA CLARA, CA 95054		 4. If Amendment, Date Original Filed(Month/Day/Year)
 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 Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)		 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)		 4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)		 5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)		 6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)		 7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
Common Stock 01/31/2006   S   34,569 D $ 4.5 25,200 D  

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number. SEC 1474 (9-02)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)		 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)		 5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)		 6. Date Exercisable and Expiration Date
(Month/Day/Year)		 7. Title and Amount of Underlying Securities
(Instr. 3 and 4)		 8. Price of Derivative Security
(Instr. 5)		 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)		 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)		 11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Employee Stock Option (Right to Buy) (1) $ 4.92               (2) 11/06/2011 Common Stock 66,581   66,581 D  
Employee Stock Option (Right to Buy) (1) $ 4.92               (2) 11/06/2011 Common Stock 49,317   49,317 D  
Employee Stock Option (Right to Buy) (1) $ 2.6               (2) 05/13/2012 Common Stock 7,243   7,243 D  
Employee Stock Option (Right to Buy) (1) $ 3.02               (3) 01/21/2015 Common Stock 113,491   113,491 D  
Employee Stock Option (Right to Buy) (1) $ 3.02               (4) 01/21/2015 Common Stock 60,355   60,355 D  
Employee Stock Option (Right to Buy) (5) $ 3.9               (6) 10/27/2013 Common Stock 50,000   50,000 D  
Employee Stock Option (Right to Buy) (7) $ 4.44               (8) 01/25/2016 Common Stock 75,000   75,000 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
PLAGA BARRY J
4150 NETWORK CIRCLE
SANTA CLARA, CA 95054		       VP & Corporate Controller  

Signatures

 /s/ Barry J. Plaga   02/01/2006
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(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) Option granted under the SeeBeyond Technology Corporation 1998 Stock Plan.
(2) Immediately.
(3) A total of 70,931 shares are fully vested and exercisable, with the remaining 42,560 shares becoming exercisable as follows: (i) 14,186 shares on January 21, 2007; and (ii) 14,187 shares on each of January 21, 2008 and January 21, 2009.
(4) A total of 37,721 shares are fully vested and exercisable, with the remaining 22,634 shares becoming exercisable as follows: (i) 7,544 shares on January 21, 2007; and (ii) 7,545 shares on each of January 21, 2008 and January 21, 2009.
(5) Option granted under the Sun Microsystems, Inc. 1996 Equity Compensation Acquisition Plan.
(6) This option vests and becomes exercisable in five equal annual installments of 10,000 shares beginning on October 3, 2006.
(7) Option granted under the Sun Microsystems, Inc. 1990 Long-Term Equity Incentive Plan.
(8) This option vests and becomes exercisable in five equal annual installments of 15,000 shares beginning on January 25, 2007.

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB number.