Abstract: A hydraulic motor vehicle brake system with a master cylinder (61) and a hydraulic power booster (24) connected upstream of the master cylinder (61), in which a pressure medium pump (1) which may be driven by an electric motor is used for providing an auxiliary hydraulic energy. The drive of the pressure medium pump (1) may be switched on by a pressure accumulator (26) which in the unbraked operation of the automotive vehicle is permanently kept on a pressure level sufficient for an initial actuation of the brake. The pressure accumulator (26) is charged by means of a pressure control valve (7) in which a valve passage (15, 17) is operable by a hydraulic pressure in the booster chamber (23) of the power booster (24) such as to ensure that upon pressurization of the booster chamber (23) a connection will be locked between the pressure accumulator (26) and the power booster (24).