Exhibit 4.5

FIFTH AMENDMENT TO

MANAGEMENT SERVICES AGREEMENT

Between

SBC INTERNATIONAL
MANAGEMENT SERVICES, INC.

A corporation duly organized under the laws of the State of Delaware, United States of America, with headquarters in
Wilmington, Delaware, USA, hereinafter SBCI-MSI, with Permanent Establishment in Mexico. Establishment in the terms provided in the Income Tax Law with address at Parque Vía 190-12th floor, Colonia Cuauhtémoc 06599 Mexico,
D. F.

and

TELEFONOS DE
MEXICO, S.A. DE C.V.

A corporation duly organized under the laws of the United Mexican States, with its principal place of business in Mexico City,
D.F., hereinafter TELMEX.

This FIFTH AMENDMENT TO MANAGEMENT SERVICES AGREEMENT, is made to be effective as of
December 31, 2005 (this Amendment), between SBC INTERNATIONAL MANAGEMENT SERVICES, INC., a corporation duly organized under the laws of the State of Delaware, United States of America, with headquarters in Wilmington, Delaware, USA,
with Permanent Establishment in the United Mexican States under the Income Tax Law with address at Parque Via 190-12thfloor, Colonia Cauahtémoc 06599 Mexico, D. F. (hereinafter SBCI-MSI) and TELEFONOS DE MEXICO, S.A. DE C.V., a corporation duly organized under the laws of the United Mexican States, with its principal place of
business in Mexico City, D.F. (hereinafter TELMEX).

WHEREAS, SBCI-MSI and TELMEX entered into that certain Management Services
Agreement dated January 2, 2001, as amended by that certain First Amendment to Management Services Agreement dated as of March 1, 2002, that Second Amendment to Management Services Agreement dated as of January 1, 2003, that Third
Amendment to Management Services Agreement dated as of November 6, 2003 and that Fourth Amendment to Management Services Agreement dated as of January 31, 2005 (as amended, the MSA); and

WHEREAS, SBCI-MSI and TELMEX desire to extend the term of and amend the MSA as provided herein.



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NOW, THEREFORE, in consideration of the premises and the mutual agreements and covenants hereinafter set
forth, the parties hereto hereby agree as follows:

SECTION 1. The parties agree that the first sentence of clause Sixth of the MSA is
hereby amended to read as follows: This agreement shall be in effect during the period starting on January 1, 2001 and ending on December 31, 2006.

SECTION 2. In accordance with the terms of Clause FOURTH of the MSA, TELMEX shall pay SBCI-MSI NINE MILLION US DOLLARS (US$9,000,000.00) plus value added tax for the sixth year of the initial term of the MSA (as such
term has been extended by this Amendment) in compensation for services rendered by SBCI-MSI thereunder. TELMEX shall make this Nine Million US Dollar (US$9,000,000.00) payment to SBCI-MSI plus value added tax in a one-time payment on
February 28, 2006 through wire transfer of immediately available funds payable in United States Dollars to a bank account designated by SBCI-MSI. Six months prior to the sixth anniversary of the commencement of the initial term of the original
MSA, the parties shall begin consultations and use best efforts to agree on compensation to be paid SBCI-MSI for the remaining term of the MSA.

SECTION 3. This Amendment and the MSA hereby are each confirmed as being in full force and effect.

SECTION 4. This Amendment may
be executed in one or more counterparts, and by the different parties hereto in separate counterparts, each of which when executed shall be deemed to be an original but all of which taken together shall constitute one and the same agreement.

SECTION 5. For interpretation and fulfillment of this Amendment, the parties expressly agree to submit to the laws of the territory and
courts of Mexico City, D.F., waiving the application of any other law or jurisdiction of any court that might have jurisdiction over them by reason of their current or future address.

This agreement is entered in Mexico City, Federal District on January 4, 2006 to be effective as of December 31, 2005.



| |  |                          |  |  |  |                           
| |  | ------------------------ |  |  |  | --------------------------
| |  | SBC INTERNATIONAL        |  |  |  | TELEFONOS DE MEXICO,      
| |  | MANAGEMENT SERVICES INC. |  |  |  | S.A. DE CV.               
| |  |                          | 
| |  | /s/ Rick Resnick         |  |  |  | /s/ Ing. Jaime Chico Pardo
| |  | By: Rick Resnick         |  |  |  | By: Ing. Jaime Chico Pardo
| |  | President SBCI  Mexico  |  |  |  | Director General          



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