A method of channel coding for transmitting data in a wireless access system includes: calculating a number C of code blocks by an equation of C=┌B/(Z−L)┐, wherein B denotes a size of an input bit sequence, wherein Z denotes a maximum size of the code blocks, and wherein L denotes a size of a cyclic redundancy check (CRC) which is to be attached to each of the code blocks; calculating a size B′ of a modified input bit sequence by an equation of B′=B+C*L; generating the code blocks based on the number C of the code blocks and the size B′ of the modified input bit sequence; and channel-coding the code blocks.