    <SEC-DOCUMENT>0001558370-19-002353-index.html : 20190321
    <SEC-HEADER>0001558370-19-002353.hdr.sgml : 20190321
    <ACCEPTANCE-DATETIME>20190321171418
    ACCESSION NUMBER:		0001558370-19-002353
    CONFORMED SUBMISSION TYPE:	PRE 14A
    PUBLIC DOCUMENT COUNT:		4
    CONFORMED PERIOD OF REPORT:	20190521
    FILED AS OF DATE:		20190321
    DATE AS OF CHANGE:		20190321

    FILER:

    	COMPANY DATA:
    		COMPANY CONFORMED NAME:			OLD SECOND BANCORP INC
    		CENTRAL INDEX KEY:			0000357173
    		STANDARD INDUSTRIAL CLASSIFICATION:	STATE COMMERCIAL BANKS [6022]
    		IRS NUMBER:				363143493
    		STATE OF INCORPORATION:			DE
    		FISCAL YEAR END:			1231

    	FILING VALUES:
    		FORM TYPE:		PRE 14A
    		SEC ACT:		1934 Act
    		SEC FILE NUMBER:	000-10537
    		FILM NUMBER:		19697744

    	BUSINESS ADDRESS:
    		STREET 1:		37 S RIVER ST
    		CITY:			AURORA
    		STATE:			IL
    		ZIP:			60507
    		BUSINESS PHONE:		6308920202

    	MAIL ADDRESS:
    		STREET 1:		37 SOUTH RIVER STREET
    		CITY:			AURORA
    		STATE:			IL
    		ZIP:			60507
    </SEC-HEADER>
    <DOCUMENT>
    <TYPE>PRE 14A
    <SEQUENCE>1
    <FILENAME>pre14a.htm
    <DESCRIPTION>PRE 14A
    <TEXT>
    Document 1 - file: pre14a.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>3
    <FILENAME>coverg001.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 3 - file: coverg001.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>4
    <FILENAME>pre14ag001.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 4 - file: pre14ag001.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>5
    <FILENAME>pre14ag002.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 5 - file: pre14ag002.jpg

    </DOCUMENT>
    </SEC-DOCUMENT>