A method is provided for recognizing the frequency bandwidth of a base station in a mobile communication system with frequency bandwidth scalability where the transmission frequency bands of base stations and mobile stations having different frequency bandwidths are overlaid with one another. The base stations transmit to a mobile station first information, including information about their frequency bandwidths at the same frequency position over a minimum frequency bandwidth with the same center frequency. The mobile station recognizes the presence of the base stations by comparing the first information from the base stations and detects the frequency bandwidth information in the first information.