An apparatus is described for extracorporeal blood treatment comprising an extracorporeal circuit (2), a first pump (13) operating at the removal line (3) of the blood, a second pump (14) operating at the return line (7) of the blood to the patient, a first blood reservoir (21) operating on the blood return line (7) upstream of the second blood pump (14) and a sensor (22) predisposed to detect at least a parameter, for example the pressure in the first reservoir； a control unit (100) connected to the first pump (13), to the second pump (14) and to the sensor (22) is configured such as to control the first pump (13) to promote removal of the blood along the removal line and the movement of the second pump (14) to promote the return of the blood to the patient along the return line, the control of the second pump being carried out on the basis of the signal emitted by the sensor acting on the first reservoir.
