A digital broadcasting system and a method for transmitting and receiving digital broadcast signal are disclosed. The method of transmitting digital broadcast signal includes convolutional encoding mobile data to build SCCC blocks, generating signaling data, forming a first data group and a second data group which includes mobile service data and the signaling data, interleaving data including the mobile service data in the first and second data groups and outputting a interleaved first data group and an interleaved second data group, wherein at least one of the SCCC blocks include an extension data block from the interleaved first data group and a data block from the interleaved second data group, transmitting the digital broadcasting signal including the first data group and the second data group.