A digital broadcasting system and method of processing data therein are disclosed. A receiving system of the digital broadcasting system includes a baseband processor unit receiving a broadcast signal including mobile service data and main service data, the mobile service data configuring an RS frame, the RS frame including the mobile service data and at least one signaling information data describing rating information of the mobile service data, a management processor unit obtaining the rating information of the mobile service data by parsing the signaling information data from the RS frame, the management processor unit determining a presence or non-presence of a viewing restriction by comparing the obtained rating information of the mobile service data to viewing restriction rating information set by a user, and a presentation processor unit blocking the mobile service data if the viewing restriction of the mobile service data is determined.