SCHEDULE 13G

Amendment No. 0 
ACCELERON PHARMA INC 
Common Stock 
Cusip #00434H108 


Cusip #00434H108 
Item 1:	Reporting Person - FMR LLC
Item 4:	Delaware
Item 5:	0 
Item 6:	0 
Item 7:	1,803,400 
Item 8:	0 
Item 9:	1,803,400 
Item 11:	6.430% 
Item 12:	    HC


Cusip #00434H108  
Item 1:	Reporting Person - Edward C. Johnson 3d 
Item 4:	United States of America
Item 5:	0 
Item 6:	0 
Item 7:	1,803,400 
Item 8:	0 
Item 9:	1,803,400 
Item 11:	6.430% 
Item 12:	IN 




	SCHEDULE 13G - TO BE INCLUDED IN 
STATEMENTS
	FILED PURSUANT TO RULE 13d-1(b) or 13d-2(b)



Item 1(a).	Name of Issuer:	

		ACCELERON PHARMA INC 

Item 1(b).	Name of Issuer's Principal Executive Offices:

		128 Sydney Street  
		Cambridge, MA  02139
		  

Item 2(a).	Name of Person Filing: 

		FMR LLC

Item 2(b).	Address or Principal Business Office or, if None, 
Residence:

		245 Summer Street, Boston, 
Massachusetts  02210

Item 2(c).	Citizenship:

		Not applicable

Item 2(d).	Title of Class of Securities:

		Common Stock 

Item 2(e).	CUSIP Number:  

		00434H108 

Item 3.	This statement is filed pursuant to Rule 13d-1(b) or 13d-2(b) 
and the person filing, FMR LLC, is a parent holding company 
in accordance with Section 240.13d-1(b)(ii)(G).  (Note:  See 
Item 7).

Item 4.	Ownership

	(a)	Amount Beneficially Owned:	1,803,400 

	(b)	Percent of Class:	6.430% 

	(c)	Number of shares as to which such 
person has:  

	(i)	sole power to vote or to direct 
the vote:	0 

	(ii)	shared power to vote or to 
direct the vote:	0 

	(iii)	sole power to dispose or to 
direct the disposition of:	1,803,400 

	(iv)	shared power to dispose or to 
direct the disposition of:	0 



Item 5.	Ownership of Five Percent or Less of a Class.

	Not applicable.

Item 6.	Ownership of More than Five Percent on Behalf of Another 
Person.

	Various persons have the right to receive or the power to 
direct the receipt of dividends from, or the proceeds from the 
sale of, the Common Stock of ACCELERON PHARMA INC.  
The interest of one person, Fidelity Select Biotechnology 
Portfolio, an investment company registered under the 
Investment Company Act of 1940, in the Common Stock of 
ACCELERON PHARMA INC, amounted to 1,599,169 shares 
or 5.702% of the total outstanding Common Stock at 
December 31, 2013. 

Item 7.	Identification and Classification of the Subsidiary Which 
Acquired the Security Being Reported on By the Parent 
Holding Company.

	See attached Exhibit A. 

Item 8.	Identification and Classification of Members of 
the Group.

	Not applicable.  See attached Exhibit A. 

Item 9.	Notice of Dissolution of Group.

	Not applicable.

Item 10.	Certification.  

	By signing below I certify that, to the best of my knowledge 
and belief, the securities referred to above were acquired in the 
ordinary course of business and were not acquired for the 
purpose of and do not have the effect of changing or 
influencing the control of the issuer of such securities and 
were not acquired in connection with or as a participant in any 
transaction having such purpose or effect.     

Signature

	After reasonable inquiry and to the best of my knowledge and 
belief, I certify that the information set forth in this statement 
is true, complete and correct. 

February 13, 2014 			
Date

 /s/ Scott C. Goebel			
Signature

Scott C. Goebel				
Duly authorized under Power of Attorney
effective as of June 1, 2008 by and on behalf of FMR LLC 
and its direct and indirect  subsidiaries


	SCHEDULE 13G - TO BE INCLUDED IN 
STATEMENTS
	FILED PURSUANT TO RULE 13d-1(b) or 13d-2(b)



	Pursuant to the instructions in Item 7 of Schedule 13G, 
Fidelity SelectCo, LLC ("SelectCo"), 1225 17th Street, Suite 
1100, Denver, Colorado 80202, a wholly-owned subsidiary of 
FMR LLC and an investment adviser registered under Section 
203 of the Investment Advisers Act of 1940, is the beneficial 
owner of 1,803,400 shares or 6.430% of the Common Stock 
outstanding of ACCELERON PHARMA INC ("the 
Company") as a result of acting as investment adviser to 
various investment companies registered under Section 8 of 
the Investment Company Act of 1940 (the "SelectCo Funds").

	Edward C. Johnson 3d and FMR LLC, through its 
control of SelectCo, and the SelectCo Funds each has sole 
power to dispose of the 1,803,400 owned by the SelectCo 
Funds.

	The ownership of one investment company, Fidelity 
Select Biotechnology Portfolio, amounted to 1,599,169 shares 
or 5.702% of the Common Stock outstanding. Fidelity Select 
Biotechnology Portfolio has its principal business office at 
245 Summer Street, Boston, Massachusetts 02210.

	Members of the family of Edward C. Johnson 3d, 
Chairman of FMR LLC, are the predominant owners, directly 
or through trusts, of Series B voting common shares of FMR 
LLC, representing 49% of the voting power of FMR LLC.  
The Johnson family group and all other Series B shareholders 
have entered into a shareholders' voting agreement under 
which all Series B voting common shares will be voted in 
accordance with the majority vote of Series B voting common 
shares.  Accordingly, through their ownership of voting 
common shares and the execution of the shareholders' voting 
agreement, members of the Johnson family may be deemed, 
under the Investment Company Act of 1940, to form a 
controlling group with respect to FMR LLC.



	SCHEDULE 13G - TO BE INCLUDED IN 
STATEMENTS
	FILED PURSUANT TO RULE 13d-1(b) or 13d-2(b)
	RULE 13d-1(f)(1)  AGREEMENT

	The undersigned persons, on February 13, 2014, agree 
and consent to the joint filing on their behalf of this Schedule 
13G in connection with their beneficial ownership of the 
Common Stock of ACCELERON PHARMA INC at 
December 31, 2013.

	FMR LLC

	By /s/ Scott C. Goebel			
	Scott C. Goebel
	Duly authorized under Power of Attorney effective as 
of June 1, 2008, by and on behalf of FMR LLC and its direct 
and indirect subsidiaries

	Edward C. Johnson 3d

	By /s/ Scott C. Goebel			
	Scott C. Goebel
	Duly authorized under Power of Attorney effective as 
of June 1, 2008, by and on behalf of Edward C. Johnson 3d

	Fidelity Select Biotechnology Portfolio

	By /s/ Scott C. Goebel			
	Scott C. Goebel
	Secretary