Ownership Submission
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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(Print or Type Responses)
1. Name and Address of Reporting Person *
  Ueunten Paul
 2. Date of Event Requiring Statement (Month/Day/Year)
10/25/2007		 3. Issuer Name and Ticker or Trading Symbol
MONOLITHIC POWER SYSTEMS INC [MPWR]
(Last)
(First)
(Middle)
6409 GUADALUPE MINES ROAD		 4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
Sr. V.P. Design Engineering
 5. If Amendment, Date Original Filed(Month/Day/Year)
(Street)

SAN JOSE, CA 95120		 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 69,500 (1)
D
 
Common Stock 153,556
I
Ueunten Trust I
Common Stock 123,900
I
Ueunten Trust II
Common Stock 40,550
I
Ueunten Trust III
Common Stock 40,550
I
Ueunten Trust IV

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
Incentive Stock Option (right to buy) 07/15/2003(2) 07/17/2012 Common Stock 58,000 $ 1.2 D  
Incentive Stock Option (right to buy) 09/10/2004(3) 09/11/2013 Common Stock 40,000 $ 1.2 D  
Incentive Stock Option (right to buy) 01/26/2006(4) 01/26/2015 Common Stock 23,271 $ 7.77 D  
Incentive Stock Option (right to buy) 06/15/2006(5) 06/15/2015 Common Stock 19,238 $ 9.32 D  
Non-Qualified Stock Option (right to buy) 01/26/2006(4) 01/26/2015 Common Stock 3,729 $ 7.77 D  
Non-Qualified Stock Option (right to buy) 06/15/2006(5) 06/15/2015 Common Stock 60,762 $ 9.32 D  
Non-Qualified Stock Option (right to buy) 10/26/2008(6) 10/26/2013 Common Stock 25,000 $ 11.85 D  
Non-Qualified Stock Option (right to buy) 07/27/2009(7) 10/26/2013 Common Stock 77,000 $ 16 D  

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
Ueunten Paul
6409 GUADALUPE MINES ROAD
SAN JOSE, CA 95120		       Sr. V.P. Design Engineering  

Signatures

Paul Ueunten 11/07/2007
**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) Includes 9,500 restricted stock units granted on 7/27/07 that vest in increments of 50% of each on 7/27/08 and 7/27/09. Also includes 60,000 shares held in an Individual Retirement Account for the benefit of the Reporting Person.
(2) A total of 94,000 shares were granted on 7/17/02. Twenty five percent (25%) of the shares vested on 7/15/03 and 1/48th of the shares vested each month thereafter.
(3) A total of 40,000 shares were granted on 9/11/03. Twenty five percent (25%) of the shares vested on 9/10/04 and 1/48th of the shares vested each month thereafter.
(4) A total of 27,000 shares were granted on 1/26/05. Twenty five percent (25%) of the shares vested on 1/26/06 and 1/48th of the shares vests each month thereafter.
(5) A total of 80,000 shares were granted on 6/15/05. Twenty five percent (25%) of the shares vested on 6/15/06 and 1/48th of the shares vests each month thereafter.
(6) A total of 25,000 shares were granted on 10/26/06. Fifty percent (50%) of the shares vest twenty-four (24) months after the grant date, and 1/48 of the shares vest monthly thereafter on the same day of the month as the grant date.
(7) A total of 77,000 shares were granted on 7/27/07. Fifty percent (50%) of the shares vest twenty-four (24) months after the grant date, and 1/48 of the shares vest monthly thereafter on the same day of the month as the grant date.

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