Abstract: There is suggested a circuit configuration for an electronically controlled anti-lock brake system, wherein upon the commencement of braking pressure control pressure fluid is pumped out of a supply reservoir (13) into the pressure chambers 7, 8) of the tandem master cylinder (1) which closes the inlet valves (14 to 17) of all wheels at the onset of the control action. It regulates the braking pressure on the imminently locking wheels by opening and closing the inlet valves and outlet valves (14 to 17 and 22 to 25) in a known fashion, while on the non-locking wheels it slowly adapts the braking pressure to the pressure prevailing in the tandem master cylinder (1) by way of pulsewise actuation at a predefinable pulse-pause ratio, that means opening and closing of the inlet valves (14 to 17).