A digital broadcasting system and a data processing method are disclosed. A receiving system of the digital broadcasting system includes a receiving unit, an SI handler, and a decoding unit. The receiving unit receives broadcast signals including mobile service data and main service data. The mobile service data configure a data group, and the data group includes a signaling information region in some of a plurality of data regions. The signaling information region may include TPC signaling data and FIC signaling data. The SI handler acquires channel configuration information of the mobile service data from the broadcast signal using pre-decided IP access information, and extracts encoding format information for each IP stream component within a corresponding virtual channel service RTP-packetized and received from the acquired channel configuration information. The decoding unit decodes the mobile service data of the corresponding IP stream component based upon the extracted encoding format information.