A motor-pump assembly for household appliances (1) such as dishwashers and washing machines, in particular for discharging water, of unusual structural simplicity, comprises a pump equipped with an impeller (2A) and a single-phase synchronous electric motor (7) with mechanical start-up equipped with a stator (5) and with a rotor (3) mutually separated by an air gap (4). The rotor (3) is of the type using permanent magnets (2B); the stator (5) is of the diapason type and is equipped with a pack core of laminations and with a pair of pole pieces (5C) that wrap coaxially around the rotor (3). The length (s) of the pole pieces (5C) of the stator (5) is at least 15% less than the length (r) of the rotor (3).