September 26, 2018

Via E-mail
Paolo Rocca
Chairman and Chief Executive Officer
Tenaris S.A.
29 Avenue de la Porte-Neuve   3rd Floor
L-2227 Luxembourg

       Re:     Tenaris S.A.
               Form 20-F for the Fiscal Year Ended December 31, 2017
               Filed April 30, 2018
               File No. 1-31518

Dear Mr. Rocca:

        We have limited our review of your filing to your contacts with
countries that have been
identified as state sponsors of terrorism, and we have the following comment.
Our review with
respect to this issue does not preclude further review by the Assistant
Director group with respect
to other issues. At this juncture, we are asking you to provide us with
information so we may
better understand your disclosure.

       Please respond to this letter within ten business days by providing the
requested
information, or by advising us when you will provide the requested response. If
you do not
believe our comment applies to your facts and circumstances, please tell us why
in your
response.

       After reviewing the information you provide in response to this comment,
we may have
additional comments.

General

   1. It appears from the website of Reliable Pipe & Tubes Ltd. that the
company is a dealer
      and distributor of your products in Sudan and Syria. Sudan and Syria are
designated by
      the U.S. Department of State as state sponsors of terrorism and are
subject to U.S.
      economic sanctions and/or export controls. You do not include disclosure
in the Form
      20-F about contacts with those countries. Please describe to us the
nature and extent of
      any past, current and anticipated contacts with Sudan and Syria,
including with their
      governments, whether through subsidiaries, distributors, affiliates or
other direct or
      indirect arrangements. Please also discuss the materiality of any
contacts, in quantitative
      terms and in terms of qualitative factors that a reasonable investor
would deem important
      in making an investment decision. Tell us the approximate dollar amounts
of any
      revenues, assets and liabilities associated with Sudan and Syria for the
last three fiscal
 Paolo Rocca
Tenaris S.A.
September 26, 2018
Page 2

       years and the subsequent interim period. Address for us the potential
impact of the
       investor sentiment evidenced by divestment and similar initiatives that
have been directed
       toward companies that have operations associated with U.S.-designated
state sponsors of
       terrorism..

        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 Pradip Bhaumik, Special Counsel, at (202) 551-3333 or me
at (202) 551-
3470 if you have any questions about the comment or our review.

                                                           Sincerely,

                                                           /s/ Cecilia Blye

                                                           Cecilia Blye, Chief
                                                           Office of Global
Security Risk


cc:    Amanda Ravitz
       Assistant Director
       Division of Corporation Finance