A digital broadcasting system for transmitting/receiving a digital broadcasting signal and a data processing method are disclosed. First program table information and second program table information, which has an identifier different from an identifier of the first program information, are multiplexed and transmitted. The first program table information describes main service data through fixed reception channel, while the second program information described mobile service data through mobile reception channel. Thus, a broadcast receiving system can receive and output the mobile service data by parsing the second program table information.