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 *
FMR LLC
   2. Issuer Name and Ticker or Trading Symbol
Ultragenyx Pharmaceutical Inc. [RARE] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
_____ Officer (give title below) __X__ Other (specify below)
See Remark 1.
(Last)
(First)
(Middle)
245 SUMMER STREET		 3. Date of Earliest Transaction (Month/Day/Year)
08/01/2014
(Street)

BOSTON, MA 02210		 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 08/01/2014   J   1,802,246 D $ 0 1,457,994 I See Footnote (1)

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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

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
FMR LLC
245 SUMMER STREET
BOSTON, MA 02210		       See Remark 1.

Signatures

 Daniel T. Gallagher, Duly authorized under Powers of Attorney, by and on behalf of FMR LLC and its direct and indirect subsidiaries, Edward C. Johnson 3d and Abigail P. Johnson   08/05/2014
**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) Beacon Bioventures Fund II Limited Partnership (BBF) made a pro-rata distribution to its limited partners, without payment of consideration, of 3,260,240 shares of Ultragenyx Pharmaceutical Inc. formerly reported by FMR LLC. BBF distributed 1,925,883 shares to Impresa Fund III Limited Partnership (IFLP), 297,343 shares to Beacon Bioventures Advisors Fund II Limited Partnership (BBAF) and 1,037,014 shares to a recipient whose shares are not subject to reporting by FMR LLC (Other Recipient). BBAF made a pro-rata distribution to its limited partners, without payment of consideration, of 10,813 shares to Fidelity Biosciences Corp. and 279,722 shares to Other Recipients. IFLP made a pro-rata distribution to its limited partners, without payment of consideration, of 485,510 shares to Other Recipients and 1,440,373 shares to persons and entities whose shares are subject to reporting by FMR LLC.
 
Remarks:
Remark 1: Edward C. Johnson 3d is a Director and the Chairman of FMR LLC and Abigail P. Johnson is a Director, the Vice Chairman and the President of FMR LLC. Members of the family of Edward C. Johnson 3d, including Abigail P. Johnson, 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. The address of Edward C. Johnson 3d and Abigail P. Johnson is c/o FMR LLC, 245 Summer Street, Boston, MA 02110.
Remark 2: Fidelity Management & Research Company, a wholly owned subsidiary of FMR LLC and an investment adviser registered under the Investment Advisers Act of 1940, is the beneficial owner of Common Stock of Ultragenyx Pharmaceutical Inc. as a result of acting as investment adviser to various investment companies registered under the Investment Company Act of 1940. FMR LLC, Edward C. Johnson 3d and Abigail P. Johnson have no pecuniary interest in the Common Stock beneficially owned by Fidelity Management & Research Company.
Remark 3: The filing of this statement shall not be deemed to be an admission that, for purposes of Section 16 of the Securities Exchange Act of 1934 or otherwise, the undersigned are the beneficial owners of any securities reported herein.

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