FORM 6 - K

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                        Report of Foreign Private Issuer
                    Pursuant to Rule 13a - 16 or 15d - 16 of
                       the Securities Exchange Act of 1934

                             As of February 1, 2006

                                  TENARIS, S.A.
                 (Translation of Registrant's name into English)

                                  TENARIS, S.A.
                           46a, Avenue John F. Kennedy
                                L-1855 Luxembourg
                    (Address of principal executive offices)

Indicate by check mark whether the registrant  files or will file annual reports
under cover Form 20-F or 40-F.

                           Form 20-F__X__ Form 40-F____

Indicate by check mark whether the  registrant  by  furnishing  the  information
contained  in this  Form is  also  thereby  furnishing  the  information  to the
Commission pursuant to Rule 12G3-2(b) under the Securities Exchange Act of 1934.

                                 Yes____ No__X__

If "Yes" is marked, indicate below the file number assigned to the registrant in
connection with Rule 12g3-2(b): 82- .

The  attached  material  is  being  furnished  to the  Securities  and  Exchange
Commission  pursuant to Rule 13a-16 and Form 6-K under the  Securities  Exchange
Act of 1934, as amended.

This report contains  Tenaris's  press release  announcing that it has completed
the acquisition of Acindar welded pipe plant.

                                    SIGNATURE

Pursuant  to the  requirements  of the  Securities  Exchange  Act of  1934,  the
Registrant  has duly  caused  this  report  to be  signed  on its  behalf by the
undersigned, thereunto duly authorized.

Date: February 1, 2006

                        Tenaris Completes Acquisition of
                           Acindar Welded Pipe Plant

    LUXEMBOURG--(BUSINESS WIRE)--Jan. 31, 2006--Tenaris S.A. (NYSE:TS)
(BCBA:TS) (BMV:TS) (BI:TEN) announced today that, through its
Argentine welded pipe subsidiary, Siat S.A., it has completed the
acquisition of the welded pipe assets and facilities of Acindar
Industria Argentina de Aceros S.A. (Acindar) located in Villa
Constitucion, Santa Fe, for US$28 million. The facilities acquired
have an annual capacity of 80,000 tons of welded pipes whose small
diameter range largely complements the range of welded pipes that
Tenaris currently produces in Argentina.
    Tenaris is a leading global manufacturer of seamless steel pipe
products and provider of pipe handling, stocking and distribution
services to the oil and gas, energy and mechanical industries and a
leading regional supplier of welded steel pipes for gas pipelines in
South America. Domiciled in Luxembourg, it has pipe manufacturing
facilities in Argentina, Brazil, Canada, Italy, Japan, Mexico, Romania
and Venezuela and a network of customer service centers present in
over 20 countries worldwide.

    CONTACT: Tenaris
             Nigel Worsnop, 1-888-300-5432
             www.tenaris.com