UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

_____________

FORM 6-K

Report of Foreign Issuer

Pursuant to Rule 13a-16 or 15d-16 of

the Securities and Exchange Act of 1934

For 7 June 2018

Commission file number: 1-13.396

Transportadora de Gas del Sur S.A.

Don Bosco 3672, Fifth Floor

1206 Capital Federal

Argentina

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

Form 20-F  X  Form 40-F   

Indicate by check mark if registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1): __

Indicate by check mark if registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7): __

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 the 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):

 City of Buenos Aires, June 7, 2018.

Messrs.

Comisión Nacional de Valores (Argentine Securities and Exchange Commission)

Bolsas y Mercados Argentinos S.A. (Argentine Stock Exchanges and Markets)

Bolsa de Comercio de Buenos Aires (Buenos Aires Stock Exchange)

(Gerencia Técnica y de Valores Negociables) (Technical and Negotiable Securities Management)

Ref.: Material Fact – TGS will make additional Midstream infrastructure investments in Vaca Muerta.

Dear Sirs,

I am writing to you in my capacity as Head of Market Relations of  Transportadora de Gas del Sur S.A. (“TGS” or the “Company”), in order to report that within the framework of the Vaca Muerta midstream project (the “Project”), TGS executed an agreed minute with the Undersecretary of Energy, Mining and Hydrocarbons of the Province of Neuquén, which is complementary to the agreed minute dated April 3, 2018 (which was notified through the material fact published on that same date) (hereinafter the “Complementary Agreed Minute”) whereby the parties commit to grant TGS an extension of the transportation concession to build and operate the Project pipeline South Tranche, which will gather the off-spec natural gas production from several hydrocarbons fields located, among others, mainly in the Vaca Muerta formation.

It should be pointed out that the execution of the Complementary Agreed Minute is subject to approval by the Provincial Executive Branch, through the issuance of the corresponding Provincial Decree in the Official Gazette of the Province of Neuquén; as from which date it will come into effect. In addition, to make the Project feasible, TGS entered into agreements with certain natural gas producers.

The South Tranche will extend from 32.5 km progressive of the North Tranche of the transportation concession to 41 km progressive of El Mangrullo-Aguada La Arena pipeline.

This new pipeline, with an associated investment of US$ 41 million, will have a transportation capacity of 883 million cubic feet per day, a length of 21 miles, a 30” diameter and will operate at a 97 Kg/cm² Higher Maximum Operating Pressure. This pipeline is expected to be in operations in April 2019.

TGS’ investments in the Vaca Muerta formation will enable the Company to magnify its midstream businesses which will consolidate its commitment to the energetic supply of Argentina.

Best regards,

Hernán Diego Flores Gómez

Head of Market Relations

SIGNATURES

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.

Transportadora de Gas del Sur S.A.

By:	/s/Alejandro M. Basso
		Name:	Alejandro M. Basso
		Title:	Vice President of Administration, Finance and Services

By:	/s/Hernán D. Flores Gómez
	Name:	Hernán Diego Flores Gómez
	Title:	Legal Affairs Vice President

Date: 7 June 2018.