January 29, 2019

Alberto J. Paracchini
President and Chief Executive Officer
Byline Bancorp, Inc.
180 North LaSalle Street, Suite 300
Chicago, IL 60601

       Re: Byline Bancorp, Inc.
           Registration Statement on Form S-4
           Filed January 9, 2019
           File No. 333-229179

Dear Mr. Paracchini:

       This is to advise you that we have not reviewed and will not review your
registration
statement.

        Please refer to Rules 460 and 461 regarding requests for acceleration.
We remind you
that the company and its management are responsible for the accuracy and
adequacy of their
disclosures, notwithstanding any review, comments, action or absence of action
by the staff.

       Please contact Christopher Dunham, Staff Attorney, at (202) 551-3783
with any
questions.



                                                            Sincerely,

                                                            Division of
Corporation Finance
                                                            Office of Financial
Services
cc:    Catherine M. Clarkin, Esq.