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

OMB APPROVAL OMB Number: 3235-0287 Expires: January 31, 2005 Estimated average burden hours per response... 0.5

(Print or Type Responses)

1. Name and Address of Reporting Person * Sullivan Eric   2. Issuer Name and Ticker or Trading Symbol bluebird bio, Inc. [BLUE] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner __X__ Officer (give title below) _____ Other (specify below) Principal Accounting Officer (Last) (First) (Middle) C/O BLUEBIRD BIO, INC., 150 SECOND STREET 3. Date of Earliest Transaction (Month/Day/Year) 08/03/2015 (Street) CAMBRIDGE, MA 02141 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 08/03/2015   M   250 A $ 20.7 3,468 D   Common Stock 08/03/2015   M   166 A $ 24.47 3,634 D   Common Stock 08/03/2015   S(1)   51 D $ 164.0888 (2) 3,583 D   Common Stock 08/03/2015   S(1)   244 D $ 165.2264 (3) 3,339 D   Common Stock 08/03/2015   S(1)   90 D $ 166.0459 (4) 3,249 D   Common Stock 08/03/2015   S(1)   31 D $ 166.8916 (5) 3,218 (6) D

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
	Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number.		SEC 1474 (9-02)

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)

$ 20.7

08/03/2015

M

250

(7)

12/02/2023

Common Stock

250

$ 0

6,750

D

Stock Option (right to buy)

$ 24.47

08/03/2015

M

166

(8)

03/03/2024

Common Stock

166

$ 0

4,838

D

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
Sullivan Eric C/O BLUEBIRD BIO, INC. 150 SECOND STREET CAMBRIDGE, MA 02141			Principal Accounting Officer

Signatures

/s/ Jason F. Cole, Attorney-in-Fact		08/05/2015
**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 sales reported in the Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on January 5, 2015.
(2)	The range in prices for the transaction reported on this line was $163.67 to $164.44. The average weighted price was $164.0888. The reporting person will provide, upon request by the SEC, the issuer or security holder of the issuer, full information regarding the number of shares sold at each separate price.
(3)	The range in prices for the transaction reported on this line was $164.72 to $165.71. The average weighted price was $165.2264. The reporting person will provide, upon request by the SEC, the issuer or security holder of the issuer, full information regarding the number of shares sold at each separate price.
(4)	The range in prices for the transaction reported on this line was $165.73 to $166.66. The average weighted price was $166.0459. The reporting person will provide, upon request by the SEC, the issuer or security holder of the issuer, full information regarding the number of shares sold at each separate price.
(5)	The range in prices for the transaction reported on this line was $166.81 to $167.06. The average weighted price was $166.8916. The reporting person will provide, upon request by the SEC, the issuer or security holder of the issuer, full information regarding the number of shares sold at each separate price.
(6)	Includes 128 shares acquired under the bluebird bio employee stock purchase plan on July 31, 2015.
(7)	This option vests over a four-year period, at a rate of twenty-five percent(25%) on November 11, 2014 and in 36 equal monthly installments thereafter.
(8)	This option vests over a four-year period, at a rate of twenty-five percent(25%) on January 1, 2015 and in 36 equal monthly installments thereafter.

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB number.