<SEC-DOCUMENT>0001564590-20-007364-index.html : 20200227
<SEC-HEADER>0001564590-20-007364.hdr.sgml : 20200227
<ACCEPTANCE-DATETIME>20200227160546
ACCESSION NUMBER:		0001564590-20-007364
CONFORMED SUBMISSION TYPE:	8-K
PUBLIC DOCUMENT COUNT:		2
CONFORMED PERIOD OF REPORT:	20200227
ITEM INFORMATION:		Regulation FD Disclosure
ITEM INFORMATION:		Financial Statements and Exhibits
FILED AS OF DATE:		20200227
DATE AS OF CHANGE:		20200227

FILER:

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			FINANCIAL INSTITUTIONS INC
		CENTRAL INDEX KEY:			0000862831
		STANDARD INDUSTRIAL CLASSIFICATION:	NATIONAL COMMERCIAL BANKS [6021]
		IRS NUMBER:				160816610
		STATE OF INCORPORATION:			NY
		FISCAL YEAR END:			1231

	FILING VALUES:
		FORM TYPE:		8-K
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-26481
		FILM NUMBER:		20661942

	BUSINESS ADDRESS:	
		STREET 1:		220 LIBERTY STREET
		CITY:			WARSAW
		STATE:			NY
		ZIP:			14569
		BUSINESS PHONE:		5857861100

	MAIL ADDRESS:	
		STREET 1:		220 LIBERTY STREET
		CITY:			WARSAW
		STATE:			NY
		ZIP:			14569
</SEC-HEADER>
<DOCUMENT>
<TYPE>8-K
<SEQUENCE>1
<FILENAME>fisi-8k_20200226.htm
<DESCRIPTION>8-K
<TEXT>
Document 1 - file: fisi-8k_20200226.htm

</DOCUMENT>
<DOCUMENT>
<TYPE>EX-99.1
<SEQUENCE>2
<FILENAME>fisi-ex991_6.htm
<DESCRIPTION>PRESS RELEASE ISSUED BY FINANCIAL INSTITUTIONS, INC. ON FEBRUARY 28, 2019
<TEXT>
Document 2 - file: fisi-ex991_6.htm

</DOCUMENT>
</SEC-DOCUMENT>