A method is provided for self-calibrating the mismatch and the direct current (DC) offset occurring in a mobile transceiver. The transmitter of the mobile terminal is used as a signal generator and the receiver thereof is used as a response characteristic measurer. The baseband processor calibrates the mismatch and the DC offset for the receiving and transmitting sides using a test signal received from the transmitter. When multiple input subcarriers are used in a mixer present on a reception stage, self-calibration is performed using multiple received test signals obtained from one transmission test signal.