A method for encoding a transport block in a wireless communication system, and a wireless apparatus therefore are discussed. The method according to one embodiment includes determining a size of the transport block; attaching a first cyclic redundancy check (CRC) code to the transport block having the determined size to produce a first CRC-attached transport block; segmenting the first CRC-attached transport block into a plurality of code blocks when a size of the first CRC-attached transport block is larger than a maximum code block size; attaching a second CRC code to each of the plurality of code blocks to produce a plurality of second CRC-attached code blocks; and encoding the second CRC-attached code blocks by a turbo-encoder. The size of the transport block is determined from among a plurality of first predetermined transport block sizes and a plurality of second predetermined transport block sizes.