A method and apparatus for transmitting a broadcast signal are provided. Data of data packets is encoded to add first parity data to the data packets. The data packets include broadcast data and signaling data for a service. The signaling data includes type information indicating a type of the service and channel information of the service. Information for acquisition of the signaling data is predefined. The encoded data is block interleaved. The block-interleaved data is convolutional interleaved. Transmission parameters are first encoded for signaling the broadcast data to add second parity data to the transmission parameters, and the first-encoded transmission parameters are second encoded at a code rate. A frame including the convolutional interleaved data and the second-encoded transmission parameters is built. The broadcast signal including the frame is transmitted. The transmission parameters include information for identifying a number of the first parity data.