A motor pump unit for a high-pressure cleaning apparatus has an electric motor and a pump. The electric motor has a motor housing that is surrounded by a cooling housing with an annular space having an annular space inlet and an annular space outlet formed therebetween. The pump has a suction inlet connected to the annular space outlet and a pressure outlet. The liquid to be transported by the pump can be supplied to the annular space inlet. In order to improve the motor pump unit such that the motor housing can have a small wall thickness and can still be cooled effectively over a large surface area, the motor housing is configured as a one-piece deep-drawn part which in a front shell area contacts stator laminations of the electric motor and in a rear shell area is arranged at a distance from rear coil heads of the stator and in the rear shell area has stiffness-enhancing depressions, wherein the front and the rear shell areas are surrounded by the annular space.