A method of controlling a shifting operation of a synchro mesh type automatic transmission in a vehicle, such as an automobile. The method includes the steps of (i) detecting the running state of the vehicle, (ii) determining an optimum gear position from the vehicle running condition, (iii) determining if the optimum gear position is higher than a gear position of the transmission, (iv) determining if the engine torque is greater than or equal to a predetermined value and reducing the engine torque below the predetermined value, if the optimum gear position is higher than the gear position of the transmission, (v) disengaging a clutch to disconnect an engine and the transmission, (vi) shifting the transmission to the optimum gear position, and (vii) engaging the clutch. Moreover, the engine torque is reduced before the clutch is released--by reducing the fuel supply to the engine--so that abrupt decelerations and declutching shocks caused by conventional shifting methods are not felt by the driver.