A broadcast receiver and a method of processing data are disclosed. The broadcast receiver includes a signal receiving unit, a transmission parameter detector, a block decoder, a storage unit, and a data manager. The signal receiving unit receives a broadcast signal multiplexed mobile broadcast service data including two-way contents and main broadcast service data. The transmission parameter detector detects the transmission parameter. The block decoder symbol-decodes the received broadcast signal included in the mobile broadcast service data in block units, based upon the detected transmission parameter. The storage unit stores the decoded two-way contents. The data manager reads a requested two-way contents from the stored two-way contents with respect to a user's select signal, and provides the requested two-way contents service.