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
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(Print or Type Responses)
1. Name and Address of Reporting Person *
SELLERS WALLACE O
  2. Issuer Name and Ticker or Trading Symbol
NATURAL GAS SERVICES GROUP INC [NGS]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director __X__ 10% Owner
_____ Officer (give title below) _____ Other (specify below)
(Last)
(First)
(Middle)
6539 UPPER YORK RD
3. Date of Earliest Transaction (Month/Day/Year)
01/31/2005
(Street)

SOLEBURY, PA 18963
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               196,091 I By Trust (1)
Common Stock               196,091 I By Trust (2)
Common Stock               103,909 D  
Common Stock               158,600 I By Wife
Common Stock 01/31/2005   X   21,936 A $ 2.5 21,936 D  
Common Stock 01/31/2005   X   9,032 A $ 3.25 9,032 D  

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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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
Nonqualified Stock Option (right to buy) (3) $ 3.88             12/31/2002 12/31/2012 Common Stock 2,500   2,500 D  
Stock Warrant (right to buy) $ 2.5 01/31/2005   X     21,936 03/31/2001 12/31/2006 Common Stock 21,936 $ 0 0 D  
Stock Warrant (right to buy) $ 3.25 01/31/2005   X     9,032 04/24/2002 04/23/2007 Common Stock 9,032 $ 0 0 D  
Nonqualified Stock Option (right to buy) (3) $ 5.55             12/31/2003 12/31/2013 Common Stock 2,500   2,500 D  
Nonqualified Stock Option (right to buy) (3) $ 9.34             01/05/2005 01/05/2015 Common Stock 2,500   2,500 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
SELLERS WALLACE O
6539 UPPER YORK RD
SOLEBURY, PA 18963
  X   X    

Signatures

 /s/ Wallace O. Sellers   02/02/2005
**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) These shares are held and registered in the name of a trust entitled "Trust under deed of Wallace O. Sellers dated June 21, 1991," under which the reporting person's spouse, Naudain Sellers, is a contingent remainder beneficiary. An unrelated third party serves as trustee of this Trust and possesses exclusive control over the investment of the securities therein. The reporting person disclaims beneficial ownership of these securities, and the filing is not an admission that the reporting person is the beneficial owner of these securities for purposes of Section 16 or for any other purpose.
(2) These shares are held by and registered in the name of a trust entitled "Trust under deed of Wallace O. Sellers dated June 22, 1971," under which the reporting person's spouse, Naudain Sellers, is a beneficiary during her lifetime. An unrelated third party serves as trustee of this Trust and possesses exclusive control over the investment of the securities therein. The reporting person disclaims beneficial ownership of these securities, and the filing is not an admission that the reporting person is the beneficial owner of these securities for purposes of Section 16 or for any other purpose.
(3) Such options were granted to the reporting person under the Natural Gas 1998 Stock Option Plan.

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