The present invention relates to a digital broadcasting system and a processing data method thereof. The present invention includes acquiring a first ensemble providing service guide information for mobile service data from a broadcast signal in which the mobile service data and main service data are multiplexed, acquiring, from the first ensemble, first program table information including information which indicates that the first ensemble provides service guide information for a second ensemble, and decoding the first program table information and acquiring service guide information for mobile service data included in the second ensemble by using the decoded first program table information.