    <SEC-DOCUMENT>0001047469-18-001377-index.html : 20180308
    <SEC-HEADER>0001047469-18-001377.hdr.sgml : 20180308
    <ACCEPTANCE-DATETIME>20180307190620
    ACCESSION NUMBER:		0001047469-18-001377
    CONFORMED SUBMISSION TYPE:	S-4/A
    PUBLIC DOCUMENT COUNT:		23
    FILED AS OF DATE:		20180308
    DATE AS OF CHANGE:		20180307

    FILER:

    	COMPANY DATA:
    		COMPANY CONFORMED NAME:			BYLINE BANCORP, INC.
    		CENTRAL INDEX KEY:			0001702750
    		STANDARD INDUSTRIAL CLASSIFICATION:	STATE COMMERCIAL BANKS [6022]
    		IRS NUMBER:				363012593

    	FILING VALUES:
    		FORM TYPE:		S-4/A
    		SEC ACT:		1933 Act
    		SEC FILE NUMBER:	333-222935
    		FILM NUMBER:		18674649

    	BUSINESS ADDRESS:
    		BUSINESS PHONE:		773-244-7000

    	MAIL ADDRESS:
    		STREET 1:		180 NORTH LASALLE STREET, SUITE 300
    		CITY:			CHICAGO
    		STATE:			IL
    		ZIP:			60601
    </SEC-HEADER>
    <DOCUMENT>
    <TYPE>S-4/A
    <SEQUENCE>1
    <FILENAME>a2234518zs-4a.htm
    <DESCRIPTION>S-4/A
    <TEXT>
    Document 1 - file: a2234518zs-4a.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-8.1
    <SEQUENCE>2
    <FILENAME>a2234518zex-8_1.htm
    <DESCRIPTION>EX-8.1
    <TEXT>
    Document 2 - file: a2234518zex-8_1.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-8.2
    <SEQUENCE>3
    <FILENAME>a2234518zex-8_2.htm
    <DESCRIPTION>EX-8.2
    <TEXT>
    Document 3 - file: a2234518zex-8_2.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-23.1
    <SEQUENCE>4
    <FILENAME>a2234518zex-23_1.htm
    <DESCRIPTION>EX-23.1
    <TEXT>
    Document 4 - file: a2234518zex-23_1.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-23.2
    <SEQUENCE>5
    <FILENAME>a2234518zex-23_2.htm
    <DESCRIPTION>EX-23.2
    <TEXT>
    Document 5 - file: a2234518zex-23_2.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-23.3
    <SEQUENCE>6
    <FILENAME>a2234518zex-23_3.htm
    <DESCRIPTION>EX-23.3
    <TEXT>
    Document 6 - file: a2234518zex-23_3.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-99.3
    <SEQUENCE>7
    <FILENAME>a2234518zex-99_3.htm
    <DESCRIPTION>EX-99.3
    <TEXT>
    Document 7 - file: a2234518zex-99_3.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-99.4
    <SEQUENCE>8
    <FILENAME>a2234518zex-99_4.htm
    <DESCRIPTION>EX-99.4
    <TEXT>
    Document 8 - file: a2234518zex-99_4.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>9
    <FILENAME>g931030.jpg
    <DESCRIPTION>G931030.JPG
    <TEXT>
    Document 9 - file: g931030.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>10
    <FILENAME>g420273.jpg
    <DESCRIPTION>G420273.JPG
    <TEXT>
    Document 10 - file: g420273.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>11
    <FILENAME>g126809.jpg
    <DESCRIPTION>G126809.JPG
    <TEXT>
    Document 11 - file: g126809.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>12
    <FILENAME>g746354.jpg
    <DESCRIPTION>G746354.JPG
    <TEXT>
    Document 12 - file: g746354.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>13
    <FILENAME>g827177.jpg
    <DESCRIPTION>G827177.JPG
    <TEXT>
    Document 13 - file: g827177.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>14
    <FILENAME>g329698.jpg
    <DESCRIPTION>G329698.JPG
    <TEXT>
    Document 14 - file: g329698.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>15
    <FILENAME>g203639.jpg
    <DESCRIPTION>G203639.JPG
    <TEXT>
    Document 15 - file: g203639.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>16
    <FILENAME>g199435.jpg
    <DESCRIPTION>G199435.JPG
    <TEXT>
    Document 16 - file: g199435.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>17
    <FILENAME>g50852lai001.gif
    <DESCRIPTION>G50852LAI001.GIF
    <TEXT>
    Document 17 - file: g50852lai001.gif

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>18
    <FILENAME>g50852mpi001.gif
    <DESCRIPTION>G50852MPI001.GIF
    <TEXT>
    Document 18 - file: g50852mpi001.gif

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>19
    <FILENAME>g50852mpi002.gif
    <DESCRIPTION>G50852MPI002.GIF
    <TEXT>
    Document 19 - file: g50852mpi002.gif

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>20
    <FILENAME>g50852mpi003.gif
    <DESCRIPTION>G50852MPI003.GIF
    <TEXT>
    Document 20 - file: g50852mpi003.gif

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>21
    <FILENAME>g50852mqi001.gif
    <DESCRIPTION>G50852MQI001.GIF
    <TEXT>
    Document 21 - file: g50852mqi001.gif

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>22
    <FILENAME>g50852mqi002.gif
    <DESCRIPTION>G50852MQI002.GIF
    <TEXT>
    Document 22 - file: g50852mqi002.gif

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>23
    <FILENAME>g50852mqi003.gif
    <DESCRIPTION>G50852MQI003.GIF
    <TEXT>
    Document 23 - file: g50852mqi003.gif

    </DOCUMENT>
    </SEC-DOCUMENT>