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 December 19, 2017

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):

Autonomous City of Buenos Aires, December 18, 2017.

Messrs.

Comisión Nacional de Valores

Bolsas y Mercados Argentinos S.A.

Bolsa de Comercio de Buenos Aires

(Gerencia Técnica y de Valores Negociables)

Mercado Abierto Electrónico S.A.

Ref.: Material fact. Section 72 and 73 Act no. 26,831. Renewal of Technical, Financial and Operational Assistance Service

Dear Sirs,

I am writing to you, in my capacity as Head of Market Relations of Transportadora de Gas del Sur S.A., in order to report that in its meeting held on December 14, 2017, the Board of Directors approved the Renewal of the Technical, Financial and Operational Assistance Service (which dates back to 1992), which currently binds TGS and Pampa Energía S.A. –as Technical Operator-. It should be noted that no remarks were made by the Gas Regulatory Body to said Renewal, pursuant to note ENRG GAL/GDyE/GT/D no. 11025 dated November 8, 2017.

In compliance with section 72 of Act no. 26,831, TGS’ Auditing Committee issued a report concluding that the terms of the above mentioned Service can be reasonable considered an arm’s length transaction. For the purpose of issuing said report, the Auditing Committee requested two (2) independent specialists to issue their own reports.

Lastly, it should be pointed out that the Auditing Committee’s report is available for consultation by accredited shareholders if so desired, at TGS’ principal office located at Don Bosco 3672 5^th floor, City of Buenos Aires (Legal Department, Ms. Valeria Kappel extension 1211).

Yours sincerely,

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: December 19, 2017