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 *
SMITH E FOLLIN
  2. Issuer Name and Ticker or Trading Symbol
CONSTELLATION ENERGY GROUP INC [CEG]
5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
CFO, CAO, Exec. VP - CEG
(Last)
(First)
(Middle)
750 E. PRATT STREET
3. Date of Earliest Transaction (Month/Day/Year)
12/21/2005
(Street)

BALTIMORE, MD 21202
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 12/21/2005   M   71,363 (1) A $ 25.08 120,895 D  
Common Stock 12/21/2005   M   206,000 (1) A $ 27.93 326,895 D  
Common Stock 12/21/2005   M   50,000 (1) A $ 31.21 376,895 D  
Common Stock 12/21/2005   M   42,227 (1) A $ 28.81 419,122 D  
Common Stock 12/21/2005   M   23,097 (1) A $ 39.63 442,219 D  
Common Stock 12/21/2005   F   271,684 (2) D $ 58.33 170,535 (3) D  
Common Stock               131.3648 I By 401(k) Plan

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
Stock Options (right to buy) (4) $ 25.08 12/21/2005   M     71,363 (1)   (5) 11/12/2011 Common Stock 71,363 $ 0 0 D  
Stock Options (right to buy) (4) $ 58.33 12/21/2005   A   46,759 (6)   12/21/2005 11/12/2011 Common Stock 46,759 $ 0 46,759 D  
Stock Options (right to buy) (4) $ 27.93 12/21/2005   M     206,000 (1)   (7) 02/05/2012 Common Stock 206,000 $ 0 0 D  
Stock Options (right to buy) (4) $ 58.33 12/21/2005   A   141,067 (6)   12/21/2005 02/05/2012 Common Stock 141,067 $ 0 141,067 D  
Stock Options (right to buy) (4) $ 31.21 12/21/2005   M     50,000 (1)   (8) 05/24/2012 Common Stock 50,000 $ 0 0 D  
Stock Options (right to buy) (4) $ 58.33 12/21/2005   A   35,939 (6)   12/21/2005 05/24/2012 Common Stock 35,939 $ 0 35,939 D  
Stock Options (right to buy) (4) $ 28.81 12/21/2005   M     42,227 (1)   (9) 05/02/2013 Common Stock 42,227 $ 0 21,113 D  
Stock Options (right to buy) (4) $ 58.33 12/21/2005   A   29,301 (6)   12/21/2005 05/02/2013 Common Stock 29,301 $ 0 29,301 D  
Stock Options (right to buy) (4) $ 39.63 12/21/2005   M     23,097 (1)   (10) 02/26/2014 Common Stock 23,097 $ 0 46,193 D  
Stock Options (right to buy) (4) $ 58.33 12/21/2005   A   18,618 (6)   12/21/2005 02/26/2014 Common Stock 18,618 $ 0 18,618 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
SMITH E FOLLIN
750 E. PRATT STREET
BALTIMORE, MD 21202
      CFO, CAO, Exec. VP - CEG  

Signatures

 Charles A. Berardesco, Attorney-in-Fact   12/22/2005
**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) At the request of the issuer, the officer has exercised all vested options held by such officer for purposes of minimizing the amount of excise taxes and tax gross-up payable by the issuer on behalf of the officer pursuant to Section 4999 of the Internal Revenue Code.
(2) Shares were withheld to pay exercise prices and taxes due on the total of 392,687 stock options exercised on 12/21/05.
(3) This amount includes shares obtained through reinvested dividends.
(4) These are employee stock options.
(5) Options vested in two installments on 7/1/02 and 7/1/03.
(6) Represents replacement options granted to the officer following exercise of existing vested options on 12/21/05. The aggregate number of replacement options received is equal to the total number of options exercised less the actual shares received by the officer upon exercise of the options.
(7) Options vested in three installments on 11/22/02, 11/23/03, and 11/24/04.
(8) Options vested in three installments on 5/24/03, 5/24/04, and 5/24/05.
(9) Options vest in three installments beginning on 5/2/04. The second installment vested on 5/2/05, and the third installment will vest on 5/2/06.
(10) Options vest in three installments beginning on 2/26/05. The second and third installments will vest on 2/26/06 and 2/26/07, respectively.

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