A device for treating blood in an extracorporeal blood circuit, the device including a centrifugal pump (4) provided with a transparent enclosure that is connected, by means of an inlet duct, to the outlet of a venous reservoir (2), the venous reservoir having an inlet that is connected to receive blood from a patient. The transparent enclosure of the pump is connected monolithically to the base of a structure that comprises a heat exchanger (5) and an oxygenator (6). The structure also supports monolithically, at the peripheral region, an arterial filter (7) that receives the blood in output from the oxygenator and is provided with a connector (7a) for coupling to an arterial line for return of the blood to the patient.
