A method and apparatus for transmitting information data using a repetition coding scheme in a wireless communication system are disclosed. The transmission method includes generating a codeword of a predetermined size Nencoded by encoding information data of a size Ninfo, and transmitting the codeword to a receiver. The codeword includes a plurality of repeated blocks based on the information data and if the information data includes an odd number of 1s, the information data of odd-numbered repeated blocks out of the plurality of repeated blocks are bit-inverted.