A method and apparatus is provided for receiving data in a receiver of a communication system. In the receiver, a first calculator calculates a Log Likelihood Ratio (LLR) value of data transmitted from a transmitter, a decoder performs iterative decoding on the transmitted data using the LLR value calculated by the first calculator. A second calculator determines whether there is an error in the decoded data by calculating an error of the data decoded by the decoder. A storage stores an LLR value of the decoded data according to the determination result of the second calculator. An adder adds up the LLR value calculated by the first calculator and the LLR value stored in the storage. A controller performs a control operation such that if the data transmitted from the transmitter is retransmitted data, the decoder performs iterative decoding using the LLR value added by the adder, and if the data transmitted from the transmitter is not retransmitted data, the decoder performs iterative decoding using the LLR value calculated by the first calculator.