An apparatus and method for channel encoding/decoding are provided which vary an iterative decoding number according to service type, data class and channel condition. A message information receiver receives information about a message to be received. A controller determines an iterative decoding number according to the message information received. A decoder iteratively decodes the received message according to the determined iterative decoding number. The message information includes a class of received data, and the class includes a bit error rate (BER). The iterative decoding number is increased for a low BER as compared to a predetermined BER. Further, the class includes a permissible time delay, and the iterative decoding number is increased for a long permissible time delay as compared to a predetermined permissible time delay. In addition, the message information includes a service type of the received data, and the iterative decoding number is decreased when the service type is a moving picture service.