<SEC-DOCUMENT>0000080255-18-002502-index.html : 20180214
<SEC-HEADER>0000080255-18-002502.hdr.sgml : 20180214
<ACCEPTANCE-DATETIME>20180214140641
ACCESSION NUMBER:		0000080255-18-002502
CONFORMED SUBMISSION TYPE:	SC 13G/A
CONFIRMING COPY:	
PUBLIC DOCUMENT COUNT:		1
FILED AS OF DATE:		20180214
DATE AS OF CHANGE:		20180214

SUBJECT COMPANY:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			TESARO, Inc.
		CENTRAL INDEX KEY:			0001491576
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				272249687
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SC 13G/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	005-86904

	BUSINESS ADDRESS:	
		STREET 1:		1000 WINTER STREET, SUITE 3300
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02451
		BUSINESS PHONE:		(339) 970-0900

	MAIL ADDRESS:	
		STREET 1:		1000 WINTER STREET, SUITE 3300
		CITY:			WALTHAM
		STATE:			MA
		ZIP:			02451

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Tesaro, Inc.
		DATE OF NAME CHANGE:	20100510

FILED BY:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			PRICE T ROWE ASSOCIATES INC /MD/
		CENTRAL INDEX KEY:			0000080255
		STANDARD INDUSTRIAL CLASSIFICATION:	SECURITY & COMMODITY BROKERS, DEALERS, EXCHANGES & SERVICES [6200]
		IRS NUMBER:				520556948
		STATE OF INCORPORATION:			MD
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SC 13G/A

	BUSINESS ADDRESS:	
		STREET 1:		100 EAST PRATT ST
		CITY:			BALTIMORE
		STATE:			MD
		ZIP:			21202
		BUSINESS PHONE:		(410)345-6603

	MAIL ADDRESS:	
		STREET 1:		P.O. BOX 89000
		CITY:			BALTIMORE
		STATE:			MD
		ZIP:			21289
</SEC-HEADER>
<DOCUMENT>
<TYPE>SC 13G/A
<SEQUENCE>1
<FILENAME>tsro13gadec17.txt
<TEXT>
Document 1 - file: tsro13gadec17.txt

</DOCUMENT>
</SEC-DOCUMENT>