"An adaptive hybrid automatic repeat request system and method include transmitting a data frame having channel-coded data and a parity bit using an initial coding rate, receiving the data frame and performing channel decoding and correcting any error that exists. When the error is not corrected, an error degree of a corresponding frame is measured and a NACK message to which the measured error degree is added is transmitted to the transmitting terminal. A parity frame is retransmitted by channel coding a parity bit corresponding to a parity level determined in accordance with the error degree added to the NACK message, and is combined with a data bit of a data frame in which error correction fails. Channel decoding and error correction are then performed."