An apparatus and a method for interacting with a mobile telephone are provided. A remote control unit receives a user command and transmits it to a TV system which recognizes the user command as a telephone function command and transmits the function command to the mobile telephone if the TV system is set to Telephone Mode. The TV system may also output data received from the mobile telephone in response to the transmitted function command. Thus, a user may interact with a mobile telephone using an interactive TV system by displaying text/image data received from the telephone and by inputting various telephone function commands using a remote control unit. Upon receiving a function command from the TV system, the mobile telephone generates output data in response to the function command and transmits itto the TV system. A display unit of the TV system displays the text/image data, and a speaker outputs the sound data. As a result, a user may conveniently interact with a mobile telephone using a display unit and a speaker of an interactive TV system with a remote control unit.