A rotor (1) for an electric motor with permanent magnets (10) has a principal axis (D), comprises a laminated core (2) delimited by a first and a second end wall (4, 5) and by a lateral surface (6) and has a hole (7) for coupling to a motor shaft (8) and a plurality of longitudinal slots (9) for housing the magnets (10); the rotor also comprises positioning devices (20) for stabilizing the magnets (10) in the slots (9).