    <SEC-DOCUMENT>0000950123-19-009056-index.html : 20190930
    <SEC-HEADER>0000950123-19-009056.hdr.sgml : 20190930
    <ACCEPTANCE-DATETIME>20190920172003
    <PRIVATE-TO-PUBLIC>
    ACCESSION NUMBER:		0000950123-19-009056
    CONFORMED SUBMISSION TYPE:	DRS/A
    PUBLIC DOCUMENT COUNT:		21
    FILED AS OF DATE:		20190920
    <PUBLIC-REL-DATE>20190930
    DATE AS OF CHANGE:		20190920

    FILER:

    	COMPANY DATA:
    		COMPANY CONFORMED NAME:			Cabaletta Bio, Inc.
    		CENTRAL INDEX KEY:			0001759138
    		STANDARD INDUSTRIAL CLASSIFICATION:	BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
    		IRS NUMBER:				000000000
    		STATE OF INCORPORATION:			DE
    		FISCAL YEAR END:			1231

    	FILING VALUES:
    		FORM TYPE:		DRS/A
    		SEC ACT:		1933 Act
    		SEC FILE NUMBER:	377-02766
    		FILM NUMBER:		191105436

    	BUSINESS ADDRESS:
    		STREET 1:		501 NORTHWICK LANE
    		CITY:			VILLANOVA
    		STATE:			PA
    		ZIP:			19085
    		BUSINESS PHONE:		(610) 659-0200

    	MAIL ADDRESS:
    		STREET 1:		501 NORTHWICK LANE
    		CITY:			VILLANOVA
    		STATE:			PA
    		ZIP:			19085
    </SEC-HEADER>
    <DOCUMENT>
    <TYPE>DRS/A
    <SEQUENCE>1
    <FILENAME>filename1.htm
    <TEXT>
    Document 1 - file: filename1.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-3.2
    <SEQUENCE>2
    <FILENAME>filename2.htm
    <TEXT>
    Document 2 - file: filename2.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-3.4
    <SEQUENCE>3
    <FILENAME>filename3.htm
    <TEXT>
    Document 3 - file: filename3.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-10.4
    <SEQUENCE>4
    <FILENAME>filename4.htm
    <TEXT>
    Document 4 - file: filename4.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-10.5
    <SEQUENCE>5
    <FILENAME>filename5.htm
    <TEXT>
    Document 5 - file: filename5.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-10.14
    <SEQUENCE>6
    <FILENAME>filename6.htm
    <TEXT>
    Document 6 - file: filename6.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-10.15
    <SEQUENCE>7
    <FILENAME>filename7.htm
    <TEXT>
    Document 7 - file: filename7.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>8
    <FILENAME>g686907g08a06.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 8 - file: g686907g08a06.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>9
    <FILENAME>g686907g24a05.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 9 - file: g686907g24a05.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>10
    <FILENAME>g686907g45x09.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 10 - file: g686907g45x09.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>11
    <FILENAME>g686907g60p26.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 11 - file: g686907g60p26.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>12
    <FILENAME>g686907g63t24.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 12 - file: g686907g63t24.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>13
    <FILENAME>g686907image10.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 13 - file: g686907image10.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>14
    <FILENAME>g686907image11.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 14 - file: g686907image11.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>15
    <FILENAME>g686907image2.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 15 - file: g686907image2.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>16
    <FILENAME>g686907image3.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 16 - file: g686907image3.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>17
    <FILENAME>g686907image4.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 17 - file: g686907image4.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>18
    <FILENAME>g686907image6.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 18 - file: g686907image6.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>19
    <FILENAME>g686907image7.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 19 - file: g686907image7.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>20
    <FILENAME>g686907image8.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 20 - file: g686907image8.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>21
    <FILENAME>g686907image9b.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 21 - file: g686907image9b.jpg

    </DOCUMENT>
    </SEC-DOCUMENT>