Ownership Submission
FORM 3
 UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF 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 *
  FMR LLC
 2. Date of Event Requiring Statement (Month/Day/Year)
01/30/2014		 3. Issuer Name and Ticker or Trading Symbol
Ultragenyx Pharmaceutical Inc. [RARE]
(Last)
(First)
(Middle)
245 SUMMER STREET		 4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director __X__ 10% Owner
_____ Officer (give title below) __X__ Other (specify below)
Edward C. Johnson 3d
 5. If Amendment, Date Original Filed(Month/Day/Year)
(Street)

BOSTON, MA 02210		 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 Beneficially Owned
1.Title of Security
(Instr. 4)		 2. Amount of Securities Beneficially Owned
(Instr. 4)		 3. Ownership Form: Direct (D) or Indirect (I)
(Instr. 5)		 4. Nature of Indirect Beneficial Ownership
(Instr. 5)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 4)		 2. Date Exercisable and Expiration Date
(Month/Day/Year)		 3. Title and Amount of Securities Underlying Derivative Security
(Instr. 4)		 4. Conversion or Exercise Price of Derivative Security 5. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 5)		 6. Nature of Indirect Beneficial Ownership
(Instr. 5)
Date Exercisable Expiration Date Title Amount or Number of Shares
Series A Convertible Preferred Stock   (1)   (1) Common Stock 9,129,063 $ (1) I by Beacon Bioventures Fund II Limited Partnership
Series B Convertible Preferred Stock   (1)   (1) Common Stock 541,634 $ (1) I by Beacon Bioventures Fund II Limited Partnership

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
FMR LLC
245 SUMMER STREET
BOSTON, MA 02210		     X   Edward C. Johnson 3d

Signatures

Scott C. Goebel, Duly authorized under Powers of Attorney effective as of June 1, 2008, by and on behalf of FMR LLC and its direct and indirect subsidiaries, and by and on behalf of Edward C. Johnson 3d 02/05/2014
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 5(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) All classes of Convertible Preferred Stock automatically convert into Common Stock, on a 3.1345-for-1 basis, upon the consummation of the initial public offering of Common Stock by the Issuer. The number of underlying shares of Common Stock reported in Column 3 does not reflect the conversion of 3.1345 Convertible Preferred Stock for 1 Common Stock.
 
Remarks:
Beacon Bioventures Advisors Fund II Limited Partnership is the general partner of Beacon Bioventures Fund II Limited Partnership. Beacon Bioventures Advisors Fund II Limited Partnership is solely managed by Northern Neck Investors LLC, its general partner and investment manager. Northern Neck Investors LLC is owned, directly or indirectly, by various shareholders and employees of FMR LLC, including certain members of the family of Edward C. Johnson 3d.

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

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