<SEC-DOCUMENT>0001193125-17-308910-index.html : 20171201
<SEC-HEADER>0001193125-17-308910.hdr.sgml : 20171201
<ACCEPTANCE-DATETIME>20171012171402
<PRIVATE-TO-PUBLIC>
ACCESSION NUMBER:		0001193125-17-308910
CONFORMED SUBMISSION TYPE:	CORRESP
PUBLIC DOCUMENT COUNT:		4
FILED AS OF DATE:		20171012

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Spero Therapeutics, Inc.
		CENTRAL INDEX KEY:			0001701108
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				000000000
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		CORRESP

	BUSINESS ADDRESS:	
		STREET 1:		675 MASSACHUSETTS AVENUE
		STREET 2:		14TH FLOOR
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02139
		BUSINESS PHONE:		857-242-1600

	MAIL ADDRESS:	
		STREET 1:		675 MASSACHUSETTS AVENUE
		STREET 2:		14TH FLOOR
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02139

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Spero Therapeutics, LLC
		DATE OF NAME CHANGE:	20170316
</SEC-HEADER>
<DOCUMENT>
<TYPE>CORRESP
<SEQUENCE>1
<FILENAME>filename1.htm
<TEXT>
Document 1 - file: filename1.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>2
<FILENAME>g431217g08q24.gif
<DESCRIPTION>GRAPHIC
<TEXT>
Document 2 - file: g431217g08q24.gif

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>3
<FILENAME>g431217g27c04.gif
<DESCRIPTION>GRAPHIC
<TEXT>
Document 3 - file: g431217g27c04.gif

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>4
<FILENAME>g431217g57r71.gif
<DESCRIPTION>GRAPHIC
<TEXT>
Document 4 - file: g431217g57r71.gif

</DOCUMENT>
</SEC-DOCUMENT>