    <SEC-DOCUMENT>0001521951-19-000017-index.html : 20190226
    <SEC-HEADER>0001521951-19-000017.hdr.sgml : 20190226
    <ACCEPTANCE-DATETIME>20190226160141
    ACCESSION NUMBER:		0001521951-19-000017
    CONFORMED SUBMISSION TYPE:	8-K
    PUBLIC DOCUMENT COUNT:		10
    CONFORMED PERIOD OF REPORT:	20190226
    ITEM INFORMATION:		Regulation FD Disclosure
    ITEM INFORMATION:		Financial Statements and Exhibits
    FILED AS OF DATE:		20190226
    DATE AS OF CHANGE:		20190226

    FILER:

    	COMPANY DATA:
    		COMPANY CONFORMED NAME:			FIRST BUSINESS FINANCIAL SERVICES, INC.
    		CENTRAL INDEX KEY:			0001521951
    		STANDARD INDUSTRIAL CLASSIFICATION:	STATE COMMERCIAL BANKS [6022]
    		IRS NUMBER:				391576570
    		STATE OF INCORPORATION:			WI
    		FISCAL YEAR END:			1231

    	FILING VALUES:
    		FORM TYPE:		8-K
    		SEC ACT:		1934 Act
    		SEC FILE NUMBER:	001-34095
    		FILM NUMBER:		19633321

    	BUSINESS ADDRESS:
    		STREET 1:		401 CHARMANY DRIVE
    		CITY:			MADISON
    		STATE:			WI
    		ZIP:			53719
    		BUSINESS PHONE:		608-238-8008

    	MAIL ADDRESS:
    		STREET 1:		401 CHARMANY DRIVE
    		STREET 2:		PO BOX 44961
    		CITY:			MADISON
    		STATE:			WI
    		ZIP:			53744

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	First Business Financial Services, Inc.
    		DATE OF NAME CHANGE:	20110527
    </SEC-HEADER>
    <DOCUMENT>
    <TYPE>8-K
    <SEQUENCE>1
    <FILENAME>fbiz4q18ceoletter8-k.htm
    <DESCRIPTION>FORM 8-K
    <TEXT>
    Document 1 - file: fbiz4q18ceoletter8-k.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-99.1
    <SEQUENCE>2
    <FILENAME>fbiz4q18ceoletterex991.htm
    <DESCRIPTION>EXHIBIT 99.1
    <TEXT>
    Document 2 - file: fbiz4q18ceoletterex991.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>3
    <FILENAME>ceoq42018final001.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 3 - file: ceoq42018final001.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>4
    <FILENAME>ceoq42018final002.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 4 - file: ceoq42018final002.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>5
    <FILENAME>ceoq42018final003.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 5 - file: ceoq42018final003.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>6
    <FILENAME>ceoq42018final004.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 6 - file: ceoq42018final004.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>7
    <FILENAME>ceoq42018final005.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 7 - file: ceoq42018final005.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>8
    <FILENAME>ceoq42018final006.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 8 - file: ceoq42018final006.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>9
    <FILENAME>ceoq42018final007.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 9 - file: ceoq42018final007.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>10
    <FILENAME>fblogo2016a14.jpg
    <DESCRIPTION>GRAPHIC
    <TEXT>
    Document 10 - file: fblogo2016a14.jpg

    </DOCUMENT>
    </SEC-DOCUMENT>