A method for controlling a turbo decoding time in a high-speed packet data communication system. In a mobile communication system which receives a control message from a packet data control channel, at the same time receives packet data from the packet data channel, performs demodulating and turbo-decoding of the packet data during a predetermined response (ACK/NAK) time delay using a demodulation result of the packet data control channel, creates a result of the turbo decoding in the form of a response (ACK/NAK) signal, and transmits the turbo decoding result, the method includes the steps of a) demodulating the control message when simultaneously receiving the control message and the packet data, and demodulating and decoding the packet data, and b) if the response time delay expires while decoding the packet data, interrupting a decoding operation of the turbo decoder.