Ownership Submission
FORM 3
 UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
  Serbun Joseph F
 2. Date of Event Requiring Statement (Month/Day/Year)
05/21/2018		 3. Issuer Name and Ticker or Trading Symbol
COMMUNITY BANK SYSTEM, INC. [CBU]
(Last)
(First)
(Middle)
C/O COMMUNITY BANK SYSTEM, INC., 5790 WIDEWATERS PARKWAY		 4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
EVP, Chief Credit Officer
 5. If Amendment, Date Original Filed(Month/Day/Year)
05/31/2018
(Street)

DEWITT, NY 13214		 6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Beneficially Owned
1.Title of Security
(Instr. 4)		 2. Amount of Securities Beneficially Owned
(Instr. 4)		 3. Ownership Form: Direct (D) or Indirect (I)
(Instr. 5)		 4. Nature of Indirect Beneficial Ownership
(Instr. 5)
Common Stock (1) 546.7621
I
By 401(k) Plan (2)
Common Stock 8,226.7224
D
 

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 4)		 2. Date Exercisable and Expiration Date
(Month/Day/Year)		 3. Title and Amount of Securities Underlying Derivative Security
(Instr. 4)		 4. Conversion or Exercise Price of Derivative Security 5. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 5)		 6. Nature of Indirect Beneficial Ownership
(Instr. 5)
Date Exercisable Expiration Date Title Amount or Number of Shares
Stock Option   (3) 01/20/2020 Common Stock 82 $ 19.48 D  
Stock Option   (4) 01/19/2021 Common Stock 2,599 $ 27.36 D  
Stock Option   (5) 03/21/2022 Common Stock 3,484 $ 28.78 D  
Stock Option   (6) 03/19/2023 Common Stock 3,858 $ 29.79 D  
Stock Option   (7) 03/18/2025 Common Stock 3,053 $ 35.36 D  
Stock Option   (8) 03/19/2024 Common Stock 2,935 $ 37.77 D  
Stock Option   (9) 03/16/2026 Common Stock 4,029 $ 38.02 D  
Stock Option   (10) 03/20/2028 Common Stock 2,779 $ 55.92 D  
Stock Option   (11) 03/15/2027 Common Stock 2,357 $ 57.12 D  

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
Serbun Joseph F
C/O COMMUNITY BANK SYSTEM, INC.
5790 WIDEWATERS PARKWAY
DEWITT, NY 13214		       EVP, Chief Credit Officer  

Signatures

/s/ Marguerite K. Geiss, pursuant to a Confirming Statement executed by Joseph F. Serbun 05/31/2018
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 5(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) This Amendment is filed to include the reporting person's Confirming Statement.
(2) The number of shares reported herein acquired pursuant to Community Bank System, Inc.'s 401(k) Plan and are based on a current plan statement.
(3) The option vested ratably on January 20, 2011, 2012, 2013, 2014 and 2015.
(4) The option vested ratably on January 19, 2012, 2013, 2014, 2015 and 2016.
(5) The option vested ratably on March 21, 2013, 2014, 2015, 2016 and 2017.
(6) The option vested ratably on March 19, 2014, 2015, 2016, 2017 and 2018.
(7) The option vests ratably on March 18, 2016, 2017, 2018, 2019 and 2020.
(8) The option vests ratably on March 19, 2015, 2016, 2017, 2018 and 2019.
(9) The option vests ratably on March 16, 2017, 2018, 2019, 2020 and 2021.
(10) The option vests ratably on March 20, 2019, 2020, 2021, 2022 and 2023.
(11) The option vests ratably on March 15, 2018, 2019, 2020, 2021 and 2022.

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