A DTV transmitting system includes a frame encoder, a randomizer, a block processor, a group formatter, a deinterleaver, and a packet formatter. The frame encoder builds an enhanced data frame and encodes the frame two times for first and second error correction, respectively. It further permutes a plurality of encoded data frames. The randomizer randomizes the permuted enhanced data, and the block processor codes the randomized data at a rate of 1/N1. The group formatter forms a group of enhanced data having one or more data regions and inserts the data coded at the rate of 1/N1 into at least one of the data regions. The deinterleaver deinterleaves the group of enhanced data, and the packet formatter formats the deinterleaved data into enhanced data packets.