A method and apparatus for decoding inner and/or outer codes in a mobile communication system. The inner and/or outer codes are decoded at low power and high speed. An inner decoder performs channel decoding and cyclic redundancy checking (CRC) on symbols received through a wireless network. An outer decoder performs outer coding on the received symbols. An erasure symbol identifier outputs information of erasure symbols in which a reception error has occurred. The reception error is determined from a result of the CRC on the received symbols. A controller counts the number of received symbols and the number of erasure symbols, and stops an operation of at least one of the inner and outer decoders when at least one of the number of received symbols and the number of erasure symbols is equal to a preset reference value.