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 *
O'Connor William Bernard
   2. Issuer Name and Ticker or Trading Symbol
MEDICINES CO /DE [MDCO] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
Chief Accounting Officer
(Last)
(First)
(Middle)
8 SYLVAN WAY		 3. Date of Earliest Transaction (Month/Day/Year)
01/16/2013
(Street)

PARSIPPANY, NJ 07054		 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 01/16/2013   M   25,000 A $ 19.98 46,933 D  
Common Stock (1) 01/16/2013   S   25,000 D $ 30 21,933 D  
Common Stock 01/16/2013   M   11,302 A $ 7.31 33,235 D  
Common Stock (1) 01/16/2013   S   11,302 D $ 30 21,933 D  
Common Stock 01/16/2013   M   13,194 A $ 17.45 35,127 D  
Common Stock 01/16/2013   S   13,194 D $ 30 21,933 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 (right to buy) $ 19.98 01/16/2013   M     25,000   (2) 04/24/2016 Common Stock 25,000 $ 0 75,000 D  
Common stock $ 7.31 01/16/2013   M     11,302   (3) 02/19/2020 Common Stock 11,302 $ 0 6,198 D  
Option (right to buy) $ 17.45 01/16/2013   M     13,194   (4) 02/18/2021 Common Stock 13,194 $ 0 20,139 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
O'Connor William Bernard
8 SYLVAN WAY
PARSIPPANY, NJ 07054		       Chief Accounting Officer  

Signatures

 /s/ William B. O'Connor   01/17/2013
**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) The common stock sales reported on this Form 4 were effected pursuant to a Rule 10b5-1 program adopted by Mr. O'Connor on March 10, 2011 as amended on March 16, 2012.
(2) As of 1/16/2013, the original grant (100,000 shares granted on 4/24/2006) was fully vested. After the exercise of the options reported hereby, as of 1/16/2013, the remaining 75,000 shares covered by this option are vested but not exercised.
(3) As of 1/16/2013, the original grant (17,500 shares granted on 2/19/2010)was vested with respect to 12,396 of the shares covered thereby and the remaining 5,104 shares covered by this option vest in equal monthly installments ending on 2/19/2014. After the exercise of the options reported hereby, as of 1/16/2013, 1,094 of the shares covered by the option were vested but not exercised.
(4) As of 1/16/2013, the original grant (33,333 shares granted on 2/18/2011) was vested with respect to 15,278 of the shares covered thereby and the remaining 18,055 shares covered by this option vest in equal monthly installments ending on 2/18/2015. After the exercise of the options reported hereby, as of 1/16/2013, 2,084 of the shares covered by the option were vested but not exercised.

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