An electronically servo-assisted bicycle gearshift and method for electronically shifting the gears of a bicycle involves the steps of: receiving a signal requesting a displacement of a chain of a bicycle gearshift from a first sprocket to a second adjacent sprocket of a gearshift group comprising at least two sprockets; if the first sprocket has a smaller diameter than the second sprocket, obtaining an upwards gear-shifting position for the second sprocket, if the first sprocket has a larger diameter than the second sprocket, obtaining a downwards gear-shifting position for the second sprocket; and driving an actuator of the gearshift group to displace a guide element of the chain in an axial direction with respect to the gearshift group from the first sprocket to the upwards gear-shifting position for the second sprocket or to the downwards gear-shifting position for the second sprocket, respectively.