Exhibit 8.1

Significant Subsidiaries and Investees

The following table sets forth our significant subsidiaries and investees accounted
for using the equity method at December 31, 2006:



|                                                              |  |                             |  |                                         |     |  |  |  |                                                                                                                                            
|------------------------------------------------------------- |  | --------------------------- |  | --------------------------------------- | --- |  |  |  | -------------------------------------------------------------------------------------------------------------------------------------------
|Name of Company                                               |  | Jurisdictionofestablishment |  | Percentageofownershipand votinginterest |     |  |  |  | Description                                                                                                                                
|Subsidiaries                                                  |  |                             |  |                                         |     |  |  |  |                                                                                                                                            
|Controladora de Servicios de Telecomunicaciones, S.A. de C.V. |  | Mexico                      |  | 100.0%                                  |     |  |  |  | Intermediate holding company                                                                                                               
|                                                              |  |                             |  |                                        
|Alquiladora de Casas, S.A. de C.V.                            |  | Mexico                      |  | 100.0%                                  |     |  |  |  | Real estate company owning our facilities                                                                                                  
|                                                              |  |                             |  |                                        
|Anuncios en Directorios, S.A. de C.V.                         |  | Mexico                      |  | 100.0%                                  |     |  |  |  | Producer of yellow pages directories                                                                                                       
|                                                              |  |                             |  |                                        
|Compañía de Teléfonos y Bienes Raíces, S.A. de C.V.           |  | Mexico                      |  | 100.0%                                  |     |  |  |  | Real estate company owning our facilities                                                                                                  
|                                                              |  |                             |  |                                        
|Consorcio Red Uno, S.A. de C.V.                               |  | Mexico                      |  | 100.0%                                  |     |  |  |  | Supplier of telecommunications network integration services and information systems                                                        
|                                                              |  |                             |  |                                        
|Teléfonos del Noroeste, S.A. de C.V.                          |  | Mexico                      |  | 100.0%                                  |     |  |  |  | Fixed-line public network concessionaire for the state of Baja California Norte and the San Luis Rio Colorado region of the state of Sonora
|                                                              |  |                             |  |                                        
|Uninet, S.A. de C.V.                                          |  | Mexico                      |  | 100.0%                                  |     |  |  |  | Provider of corporate networks and Internet access services to Telmex and corporate customers                                              
|                                                              |  |                             |  |                                        
|Embratel Participações S.A.                                   |  | Brazil                      |  | 97.0%                                   | (1) |  |  |  | Intermediate holding company of subsidiary that provides domestic and international long distance, local and data services in Brazil       
|                                                              |  |                             |  |                                        
|Empresa Brasileira de Telecomunicações S.A.  EMBRATEL        |  | Brazil                      |  | 96.0%                                   |     |  |  |  | Provider of domestic and international long distance, local and data services in Brazil                                                    
|                                                              |  |                             |  |                                        
|Star One S.A.                                                 |  | Brazil                      |  | 76.8%                                   |     |  |  |  | Provider of satellite services in Brazil                                                                                                   
|                                                              |  |                             |  |                                        
|PrimeSys Soluções Empresariais S.A.                           |  | Brazil                      |  | 96.0%                                   |     |  |  |  | Provider of high level value-added services, such as net integration and outsourcing                                                       
|                                                              |  |                             |  |                                        
|Telmex do Brasil, Ltda.                                       |  | Brazil                      |  | 97.0%                                   |     |  |  |  | Provider of telecommunications services to corporate customers in Brazil                                                                   
|                                                              |  |                             |  |                                        
|Telmex Chile Holding, S.A.                                    |  | Chile                       |  | 100.0%                                  |     |  |  |  | Holding company for assets acquired from AT&T Latin America Corp. in Chile                                                                 
|                                                              |  |                             |  |                                        
|Telmex Corp. S.A. (formerly Chilesat Corp S.A.)               |  | Chile                       |  | 99.7%                                   |     |  |  |  | Intermediate holding company whose subsidiaries provide long distance, Internet access and data network services in Chile                  
|                                                              |  |                             |  |                                        
|Techtel-LMDS Comunicaciones Interactivas, S.A.                |  | Argentina                   |  | 100.0%                                  |     |  |  |  | Provider of wireless voice, data and video transfer services and local and long distance fixed-line voice services in Argentina            



---

|                                   |  |                             |  |                                         |     |  |  |  |                                                                                                                                                                                                                                                     
|---------------------------------- |  | --------------------------- |  | --------------------------------------- | --- |  |  |  | ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|Name of Company                    |  | Jurisdictionofestablishment |  | Percentageofownershipand votinginterest |     |  |  |  | Description                                                                                                                                                                                                                                         
|Telmex Argentina S.A.              |  | Argentina                   |  | 100.0%                                  |     |  |  |  | Provider of telecommunications services to corporate customers in Argentina                                                                                                                                                                         
|                                   |  |                             |  |                                        
|Metrored Telecomunicaciones S.R.L. |  | Argentina                   |  | 100.0%                                  |     |  |  |  | Provider of data services in Argentina                                                                                                                                                                                                              
|                                   |  |                             |  |                                        
|Telmex Colombia S.A.               |  | Colombia                    |  | 100.0%                                  |     |  |  |  | Provider of telecommunications services to corporate customers in Colombia                                                                                                                                                                          
|                                   |  |                             |  |                                        
|Superview Telecomunicaciones, S.A. |  | Colombia                    |  | 99.2%                                   |     |  |  |  | Cable television provider in Colombia                                                                                                                                                                                                               
|                                   |  |                             |  |                                        
|Telmex Perú S.A.                   |  | Peru                        |  | 100.0%                                  |     |  |  |  | Provider of telecommunications services to corporate customers in Peru                                                                                                                                                                              
|                                   |  |                             |  |                                        
|Sección Amarilla USA L.L.C.        |  | Delaware                    |  | 80.0%                                   |     |  |  |  | Publisher of Spanish-language telephone directories with presence in 19 states in the United States                                                                                                                                                 
|                                   |  |                             |  |                                        
|Telmex USA, L.L.C.                 |  | Delaware                    |  | 100.0%                                  |     |  |  |  | Authorized long distance service re-seller, telephone card sales, receipt of payments for lines in Mexico (installation expenses and monthly rental) and authorized by the FCC to provide
facility-based long distance services in the United States
|Affiliated companies               |  |                             |  |                                         |     |  |  |  |                                                                                                                                                                                                                                                     
|Net Serviços de Comunicação S.A.   |  | Brazil                      |  | 38.6%                                   | (2) |  |  |  | Provider of cable television and local telephone services and bidirectional broadband Internet access services in Brazil                                                                                                                            
|                                   |  |                             |  |                                        
|Grupo Telvista S.A. de C.V.        |  | Mexico                      |  | 45.0%                                   |     |  |  |  | Provider of telemarketing services in the United States and Mexico                                                                                                                                                                                  
|                                   |  |                             |  |                                        
|2Wire, Inc.                        |  | California                  |  | 13.0%                                   |     |  |  |  | Broadband network equipment and service provider for residential and small-business customers                                                                                                                                                       

---

|(1) | At December 31, 2006, Telmex held 98.0% of the voting shares of Embratel Participações S.A., or Embratel.
|--- | ---------------------------------------------------------------------------------------------------------

|(2) | Corresponds to Telmexs indirect interest in Net Serviços de Comunicação S.A., or Net, held through Embratel. The direct and indirect interest of Embratel
in Net at December 31, 2006 was 39.9%.
|--- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------