    <SEC-DOCUMENT>0000357173-20-000042-index.html : 20200722
    <SEC-HEADER>0000357173-20-000042.hdr.sgml : 20200722
    <ACCEPTANCE-DATETIME>20200722164645
    ACCESSION NUMBER:		0000357173-20-000042
    CONFORMED SUBMISSION TYPE:	8-K
    PUBLIC DOCUMENT COUNT:		20
    CONFORMED PERIOD OF REPORT:	20200722
    ITEM INFORMATION:		Results of Operations and Financial Condition
    ITEM INFORMATION:		Financial Statements and Exhibits
    FILED AS OF DATE:		20200722
    DATE AS OF CHANGE:		20200722

    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:		8-K
    		SEC ACT:		1934 Act
    		SEC FILE NUMBER:	000-10537
    		FILM NUMBER:		201041916

    	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-20200722x8k.htm
    <DESCRIPTION>8-K
    <TEXT>
    Document 1 - file: osbc-20200722x8k.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-99.1
    <SEQUENCE>2
    <FILENAME>osbc-20200722ex991b82582.htm
    <DESCRIPTION>EX-99.1
    <TEXT>
    Document 2 - file: osbc-20200722ex991b82582.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-99.2
    <SEQUENCE>3
    <FILENAME>osbc-20200722ex99202aaa7.htm
    <DESCRIPTION>EX-99.2
    <TEXT>
    Document 3 - file: osbc-20200722ex99202aaa7.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>4
    <FILENAME>osbc-20200722ex991b82582001.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 4 - file: osbc-20200722ex991b82582001.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>5
    <FILENAME>osbc-20200722ex99202aaa7001.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 5 - file: osbc-20200722ex99202aaa7001.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>6
    <FILENAME>osbc-20200722ex99202aaa7002.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 6 - file: osbc-20200722ex99202aaa7002.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>7
    <FILENAME>osbc-20200722ex99202aaa7003.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 7 - file: osbc-20200722ex99202aaa7003.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>8
    <FILENAME>osbc-20200722ex99202aaa7004.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 8 - file: osbc-20200722ex99202aaa7004.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>9
    <FILENAME>osbc-20200722ex99202aaa7005.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 9 - file: osbc-20200722ex99202aaa7005.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>10
    <FILENAME>osbc-20200722ex99202aaa7006.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 10 - file: osbc-20200722ex99202aaa7006.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>11
    <FILENAME>osbc-20200722ex99202aaa7007.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 11 - file: osbc-20200722ex99202aaa7007.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>12
    <FILENAME>osbc-20200722ex99202aaa7008.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 12 - file: osbc-20200722ex99202aaa7008.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>13
    <FILENAME>osbc-20200722ex99202aaa7009.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 13 - file: osbc-20200722ex99202aaa7009.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>14
    <FILENAME>osbc-20200722ex99202aaa7010.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 14 - file: osbc-20200722ex99202aaa7010.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>15
    <FILENAME>osbc-20200722ex99202aaa7011.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 15 - file: osbc-20200722ex99202aaa7011.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>16
    <FILENAME>osbc-20200722ex99202aaa7012.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 16 - file: osbc-20200722ex99202aaa7012.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>17
    <FILENAME>osbc-20200722ex99202aaa7013.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 17 - file: osbc-20200722ex99202aaa7013.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>18
    <FILENAME>osbc-20200722ex99202aaa7014.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 18 - file: osbc-20200722ex99202aaa7014.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>19
    <FILENAME>osbc-20200722ex99202aaa7015.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 19 - file: osbc-20200722ex99202aaa7015.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>20
    <FILENAME>osbc-20200722x8k001.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 20 - file: osbc-20200722x8k001.jpg

    </DOCUMENT>
    </SEC-DOCUMENT>