A DTV transmitting system includes an encoder, a randomizer, a block processor, a group formatter, a deinterleaver, and a packet formatter. The encoder codes enhanced data for error correction, permutes the coded data, and further codes the permuted data for error detection. The randomizer randomizes the coded enhanced data, and the block processor codes the randomized data at an effective coding rate of 1/H. The group formatter forms a group of enhanced data having data regions, and inserts the coded enhanced data 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 corresponding data bytes.