    <SEC-DOCUMENT>0000357173-17-000050-index.html : 20170901
    <SEC-HEADER>0000357173-17-000050.hdr.sgml : 20170901
    <ACCEPTANCE-DATETIME>20170901125911
    ACCESSION NUMBER:		0000357173-17-000050
    CONFORMED SUBMISSION TYPE:	8-K
    PUBLIC DOCUMENT COUNT:		7
    CONFORMED PERIOD OF REPORT:	20170901
    ITEM INFORMATION:		Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers: Compensatory Arrangements of Certain Officers
    ITEM INFORMATION:		Financial Statements and Exhibits
    FILED AS OF DATE:		20170901
    DATE AS OF CHANGE:		20170901

    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:			1215

    	FILING VALUES:
    		FORM TYPE:		8-K
    		SEC ACT:		1934 Act
    		SEC FILE NUMBER:	000-10537
    		FILM NUMBER:		171065691

    	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>8-K
    <SEQUENCE>1
    <FILENAME>osbc-20170901x8k.htm
    <DESCRIPTION>8-K
    <TEXT>
    Document 1 - file: osbc-20170901x8k.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-10.1
    <SEQUENCE>2
    <FILENAME>osbc-20170901ex101e63d5f.htm
    <DESCRIPTION>EX-10.1
    <TEXT>
    Document 2 - file: osbc-20170901ex101e63d5f.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-10.2
    <SEQUENCE>3
    <FILENAME>osbc-20170901ex1028693d1.htm
    <DESCRIPTION>EX-10.2
    <TEXT>
    Document 3 - file: osbc-20170901ex1028693d1.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>4
    <FILENAME>osbc20170901ex101e63d5f001.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 4 - file: osbc20170901ex101e63d5f001.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>5
    <FILENAME>osbc20170901ex101e63d5f002.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 5 - file: osbc20170901ex101e63d5f002.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>6
    <FILENAME>osbc20170901ex101e63d5f003.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 6 - file: osbc20170901ex101e63d5f003.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>7
    <FILENAME>osbc20170901x8k001.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 7 - file: osbc20170901x8k001.jpg

    </DOCUMENT>
    </SEC-DOCUMENT>