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 *
SCHLEIFER MARK A
  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 of IP Engineering
(Last)
(First)
(Middle)
1015 31ST ST., NW
3. Date of Earliest Transaction (Month/Day/Year)
02/15/2005
(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 02/15/2005(1)   C(1)   479,230 (1) A $ 0 479,230 (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
Series H Convertible Preferred Stock (1) $ 0 02/15/2005(1)   C(1)     632 (1) 10/10/2003(1)   (1) common stock (1) 479,230 $ 0 0 (1) D  
Option to purchase Series H Convertible Preferred Stock (2) $ 0.01 02/15/2005(2)   C(2)     250 (2) 06/01/2005(2) 09/08/2014 common stock (2) 192,307 $ 0 0 (2) D  
Option to purchase common stock (2) $ 0 02/15/2005(2)   C(2)   192,307 (2)   06/01/2005(2) 09/08/2014 common stock (2) 192,307 $ 0 192,307 (2) D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
SCHLEIFER MARK A
1015 31ST ST., NW
WASHINGTON, DC 20007
      VP of IP Engineering  

Signatures

 Mark Schleifer   02/15/2005
**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) On February 15, 2005 Mr. Schleifer's 623 shares of Series H Convertible Preferred Stock were converted by action of the stockholders into 479,230 shares of common stock at a rate of 769.2307692 shares of common stock for each share of Series H Preferred Stock. The common stock is subject to the same vesting provisions applicable to the original Series H Preferred Stock.
(2) On February 15, 2005 Mr. Schleifer's option to acquire 250 shares of Series H Convertible Preferred Stock was converted by action of the stockholders into 192,307 shares of common stock at a rate of 769.2307692 shares of common stock for each share of Series H Preferred Stock. The common stock is subject to the same vesting provisions applicable to the original option to acquire Series H Preferred Stock: 25% of the option will vest on June 1, 2005 and monthly thereafter in 1/48th increments over the following 36 months until fully vested at the end of four years; vesting will accelerate under certain circumstances.

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