A method and an apparatus for easily updating map data in real time, using a device employing map data or a navigation system, through a transport protocol expert group (TPEG) service, and a computer-readable medium storing a computer program for executing the method, as provided. The method includes determining if the map data has changed using location information received from at least one of a broadcasting network, the Internet, and a transmission medium; and updating the map data based on the location information if the map data has changed.