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 *
ONEILL TIMOTHY G
   2. Issuer Name and Ticker or Trading Symbol
COGENT COMMUNICATIONS GROUP INC [COI] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
VP Field Engineering
(Last)
(First)
(Middle)
1015 31ST ST., NW		 3. Date of Earliest Transaction (Month/Day/Year)
12/05/2005
(Street)

WASHINGTON, DC 20007		 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 12/05/2005   S   1,000 D $ 6 22,962 (1) D  
common stock 12/05/2005   S   4,000 D $ 5.88 18,962 (1) D  

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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
Option to purchase common stock $ 0             06/01/2005 09/08/2014 common stock 13,462   13,462 (2) D  
Option to purchase common stock $ 4.88 (3) 10/26/2005   A   10,000 (3)   10/26/2005(2) 10/26/2015 common stock 10,000 $ 0 23,462 (4) D (4)  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
ONEILL TIMOTHY G
1015 31ST ST., NW
WASHINGTON, DC 20007		       VP Field Engineering  

Signatures

 Timothy O'Neill   12/06/2005
**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) This amount includes 18,962 shares owned by Mr. O'Neill as previously reported on various forms 4. Of this total 14,471 shares are vested and the remainder will vest by August 1, 2006. All share amounts reflect the 1-for-20 reverse stock split effected by the Company on March 23, 2005.
(2) The options to acquire 13,462 shares of common stock reflect the forced conversion into common stock effected in February, 2005 and a 1-for-20 reverse stock split effected on March 23, 2005 concerning an option to acquire 350 shares of Series H preferred stock granted to Mr. O'Neill in 2003. Mr. O'Neill has previously reported this grant on a form 4.
(3) On October 26, 2005 the Board of Directors of the Company approved a grant to Mr. O'Neill of options to purchase 10,000 shares of common stock at a purchase price of $4.88 per share. Options vest quarterly over 4 years in increments of 625 shares. Options are exercisable for a period of 10 years from date of grant.
(4) Reflects options to purchase 13,462 and 10,000 shares of common stock owned by Mr. O'Neill.

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