December 20, 2018

Arnon Rosenthal, Ph.D.
Chief Executive Officer
Alector, Inc.
151 Oyster Point Boulevard
Suite 300
South San Francisco, CA 94080

       Re: Alector, Inc.
           Draft Registration Statement on Form S-1
           Response Dated December 17, 2018
           CIK No. 0001653087

Dear Dr. Rosenthal:

      We have reviewed your amended draft registration statement and have the
following
comments. In some of our comments, we may ask you to provide us with
information so we
may better understand your disclosure.

       Please respond to this letter by providing the requested information and
either submitting
an amended draft registration statement or publicly filing your registration
statement on
EDGAR. If you do not believe our comments apply to your facts and circumstances
or do not
believe an amendment is appropriate, please tell us why in your response.

      After reviewing the information you provide in response to these comments
and your
amended draft registration statement or filed registration statement, we may
have additional
comments.

Response Dated December 17, 2018

Notes to Consolidated Financial Statements
2. Summary of Significant Accounting Policies
Revenue recognition, page F-10

1.     Please revise the disclosure you proposed in response to comment 3 with
respect to the
       $242.8 million of milestones per program to describe the triggering
events and to state
       whether it includes multiple indications and, if so, the number of
indications.

       You may contact Keira Nakada at (202) 551-3659 or Jim Rosenberg, Senior
Assistant
Chief Accountant, at (202) 551-3679 if you have questions regarding comments on
the financial
 Arnon Rosenthal, Ph.D.
Alector, Inc.
December 20, 2018
Page 2

statements and related matters. Please contact J. Nolan McWilliams,
Attorney-Advisor, at (202)
551-3217 or Dietrich King, Attorney-Advisor, at (202) 551-8071 with any other
questions.



                                                           Sincerely,
FirstName LastNameArnon Rosenthal, Ph.D.
                                                           Division of
Corporation Finance
Comapany NameAlector, Inc.
                                                           Office of Healthcare
& Insurance
December 20, 2018 Page 2
cc:       Tony Jeffries
FirstName LastName