A transmitting system and a method for processing data are disclosed herein. The transmitting system includes a service multiplexer and at least one transmitter located in a remote position from the service multiplexer. Herein, the service multiplexer generates an RS frame having the size of N (row)×187 (column) bytes including at least one type of mobile service data, packetizes the RS frame into a plurality of mobile service data packets, and multiplexes the packetized mobile service data packets with a main service data packet at a predetermined data rate, thereby transmitting the multiplexed data packets. Herein, each mobile service data packet is configured of a TS header and a data region, and the data region is configured of at least one of a payload region and an adaptation field region.