A digital broadcasting system and method of processing data therein are disclosed. The present invention includes a baseband processor unit receiving a broadcast signal including mobile service data and main service data, wherein the mobile service data can configure an RS frame and wherein the RS frame includes at least one of the mobile service data and a notification message and at least one of a first signaling information describing signaling information of a virtual channel for transmitting the mobile service data and a second signaling information describing signaling information on a notification channel for transmitting the notification message, a management processor unit accessing the notification message by parsing the second signaling information from the RS frame, the management processor unit processing the accessed notification message, the management processor unit storing the processed notification message in a storage device, and a presentation processor unit outputting the processes notification message to an output device.