<SEC-DOCUMENT>0001415889-25-004277-index.html : 20250214
<SEC-HEADER>0001415889-25-004277.hdr.sgml : 20250214
<ACCEPTANCE-DATETIME>20250214183142
ACCESSION NUMBER:		0001415889-25-004277
CONFORMED SUBMISSION TYPE:	SCHEDULE 13G/A
PUBLIC DOCUMENT COUNT:		2
FILED AS OF DATE:		20250214
DATE AS OF CHANGE:		20250214

SUBJECT COMPANY:	

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Day One Biopharmaceuticals, Inc.
		CENTRAL INDEX KEY:			0001845337
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		ORGANIZATION NAME:           	03 Life Sciences
		IRS NUMBER:				832415215
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SCHEDULE 13G/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	005-92582
		FILM NUMBER:		25631691

	BUSINESS ADDRESS:	
		STREET 1:		2000 SIERRA POINT PARKWAY, SUITE 501
		CITY:			BRISBANE
		STATE:			CA
		ZIP:			94005
		BUSINESS PHONE:		650 484-0899

	MAIL ADDRESS:	
		STREET 1:		2000 SIERRA POINT PARKWAY, SUITE 501
		CITY:			BRISBANE
		STATE:			CA
		ZIP:			94005

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Day One Biopharmaceuticals Holding Co LLC
		DATE OF NAME CHANGE:	20210209

FILED BY:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			RA CAPITAL MANAGEMENT, L.P.
		CENTRAL INDEX KEY:			0001346824
		ORGANIZATION NAME:           	
		IRS NUMBER:				830406777
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		SCHEDULE 13G/A

	BUSINESS ADDRESS:	
		STREET 1:		200 BERKELEY STREET, 18TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116
		BUSINESS PHONE:		617-778-2500

	MAIL ADDRESS:	
		STREET 1:		200 BERKELEY STREET, 18TH FLOOR
		CITY:			BOSTON
		STATE:			MA
		ZIP:			02116

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	RA CAPITAL MANAGEMENT, LLC
		DATE OF NAME CHANGE:	20051213
</SEC-HEADER>
<DOCUMENT>
<TYPE>SCHEDULE 13G/A
<SEQUENCE>1
<FILENAME>primary_doc.xml
<TEXT>
Document 1 - file: primary_doc.html

Document 1 - RAW XML: primary_doc.xml

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-99.1
<SEQUENCE>2
<FILENAME>ex-99-02142025_110242.htm
<DESCRIPTION>JOINT FILING AGREEMENT
<TEXT>
Document 2 - file: ex-99-02142025_110242.htm

</DOCUMENT>
</SEC-DOCUMENT>