A hydraulic control unit for a motor-vehicle braking system includes a pump (32) delivering hydraulic fluid under pressure, the pump being capable of being controlled by an electronic control unit (ECU) and supplying the hydraulic fluid for at least one braking device (22) which is coupled to a wheel of the vehicle, and also a first reservoir (34) for pressureless hydraulic fluid, which is assigned to the pump (32) on the input side, and a second reservoir (36) for hydraulic fluid under pressure, which is assigned to the pump (32) on the output side. In order to design the control unit for good packaging and installation space considerations, the pump (32), the first reservoir (34), and the second reservoir (36) are arranged in a common casing (60), and integrated as an electrohydraulic modular unit.