A device for pumping blood in an extracorporeal circuit includes a centrifugal pump that suctions the blood to be pumped via a venous hose line connected to a suction side of the pump and releases it via an arterial hose line connected to a release side of the pump. The device includes a flow sensor that detects a released quantity on the release side of the pump and emits a measurement signal corresponding to the released quantity, a pressure sensor that detects the pressure on the release side of the pump and emits a measurement signal corresponding to the pressure, and an evaluation unit to which the measurement signals of the sensors are fed and which determines a value corresponding to the pressure on the suction side of the pump, taking into consideration the two measurements signals and the rotational speed of the centrifugal pump.
