The method monitors a gear-change operation in a motor vehicle provided with an engine whose crankshaft is connected to a transmission having a gearbox) comprising first and second primary shafts connectable to the crankshaft of the engine by respective friction clutches controlled by corresponding actuators, and a secondary or output shaft connectable to the primary shafts by gears defining a plurality of velocity ratios or gears. The method comprises the operation of verifying and validating the detection of the disengagement of the previously engaged gear by detecting the angular velocity of the primary shaft corresponding to the gear to be disengaged, and comparing the detected value of said angular velocity with at least one reference angular velocity.