The invention relates to a blood pump which comprises a housing with an inlet (4) arranged upstream and an outlet (6) arranged downstream and which comprises a rotatably mounted rotor (20) with an axis (15) and an impeller (28). The rotor further comprises a cylinder sleeve or a cylinder (24), and the impeller is arranged on an outer surface of the cylinder. The rotor is magnetically mounted in an axial direction and comprises at least one first ring (32) which is secured to the impeller, which radially encircles the exterior of the impeller, and which is magnetized in the axial direction. The rotor further comprises a second magnetized ring portion (14) which encircles the exterior of the first ring in order to form an axial magnetic bearing.