<SEC-DOCUMENT>0000357173-20-000033-index.html : 20200625
<SEC-HEADER>0000357173-20-000033.hdr.sgml : 20200625
<ACCEPTANCE-DATETIME>20200625152233
ACCESSION NUMBER:		0000357173-20-000033
CONFORMED SUBMISSION TYPE:	11-K
PUBLIC DOCUMENT COUNT:		2
CONFORMED PERIOD OF REPORT:	20191231
FILED AS OF DATE:		20200625
DATE AS OF CHANGE:		20200625

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:		11-K
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-10537
		FILM NUMBER:		20989047

	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>11-K
<SEQUENCE>1
<FILENAME>c173-20191231x11k.htm
<DESCRIPTION>11-K
<TEXT>
Document 1 - file: c173-20191231x11k.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>GRAPHIC
<SEQUENCE>2
<FILENAME>c173-20191231x11k001.jpg
<DESCRIPTION>GRAPHIC
<TEXT>
Document 2 - file: c173-20191231x11k001.jpg

</DOCUMENT>
</SEC-DOCUMENT>