The present invention is directed to a digital broadcast system and a data processing method. A broadcast signal in which mobile service data and main service dataare multiplexed is transmitted and received. Then, in a broadcasting receiver, the program table informationincluding information about a service or a program of an ensemble is parsed according to an identifier of the ensemble in which the mobile service data are multiplexed, in the received broadcast signal. And a mobile service is outputted by using the mobile service data and the parsed program table information.