SEC FORM 3

SEC Form 3

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
or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person^*

SEIDENBERG BETH C

(Last)

(First)

(Middle)

2750 SAND HILL ROAD

(Street)

MENLO PARK

94025

(City)

(State)

(Zip)

2. Date of Event Requiring Statement (Month/Day/Year)
06/27/2012

3. Issuer Name and Ticker or Trading Symbol
TESARO, Inc. [ TSRO ]

4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director	10% Owner
	Officer (give title below)	Other (specify below)

5. If Amendment, Date of 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

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)

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: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
1. Title of Derivative Security (Instr. 4)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares	4. Conversion or Exercise Price of Derivative Security	5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5)	6. Nature of Indirect Beneficial Ownership (Instr. 5)
Series B Preferred Stock	⁽¹⁾	⁽¹⁾	Common Stock	1,816,748	⁽¹⁾	I	See Footnotes⁽²⁾⁽³⁾
Series B Preferred Stock	⁽¹⁾	⁽¹⁾	Common Stock	153,695	⁽¹⁾	I	See Footnotes⁽³⁾⁽⁴⁾

Explanation of Responses:

1. The reported securities are convertible at any time, in whole or in part, at the option of the holder, have no expiration date, and will convert into shares of common stock immediately prior to the closing of the Issuer's initial public offering.

2. The shares are held directly by Kleiner Perkins Caufield & Byers XIV, LLC ("KPCB XIV"). The managing member of KPCB XIV is KPCB XIV Associates, LLC ("KPCB XIV Associates"), of which the Reporting Person is a member. The voting and dispositive control over the shares is shared by the managing members of KPCB XIV Associates and the Reporting Person. The shares are held for convenience in the name of "KPCB Holdings, Inc. as nominee."

3. The Reporting Person disclaims beneficial ownership over all Issuer shares held for convenience in the name of "KPCB Holdings, Inc. as nominee," except to the extent of her pecuniary interest therein and this filing is not an admission that the Reporting Person is the beneficial owner of these shares for the purposes of Section 16 or for any other purpose.

4. The shares are held directly by KPCB XIV Founders Fund, LLC ("KPCB XIV Founders"). The managing member of KPCB XIV Founders is KPCB XIV Associates, LLC ("KPCB XIV Associates"), of which the Reporting Person is a member. The voting and dispositive control over the shares is shared by the managing members of KPCB XIV Associates and the Reporting Person. The shares are held for convenience in the name of "KPCB Holdings, Inc. as nominee."

Remarks:

Exhibit List Exhibit 24 - Power of Attorney

	/s/ Paul Vronsky, Attorney-in-Fact	06/27/2012
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* 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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
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 Number.