The present invention discloses a receiving system and a method of processing data to receiving and processing mobile service data. The receiving system may include a signal receiving unit, a demodulating unit, a data processor, and a middleware engine. The signal receiving unit receives a broadcasting signal, which includes IP packets, payload of the IP packets including a DSM-CC module data part and a DSM-CC header, the DSM-CC module data part including a plurality of DSM-CC objects, and the DSM-CC header including identification information for identifying the DSM-CC module. The demodulating unit demodulates the received broadcasting signal including IP packets. The data processor extracts a plurality of DSM-CC objects of a corresponding payload with reference to DSM-CC header information of the IP packets demodulated by the demodulating unit and configuring a DSM-CC module, which includes identification information and the extracted DSM-CC objects. The middleware engine provides a data broadcasting service by driving application corresponding to the DSM-CC module.