Abstract: A magnetically operated blood pump includes a rotor with an impeller that rotates within a housing, and the housing fastens to a driver that preferably electromagnetically controls the speed and disposition of the impeller in response to sensed conditions. The impeller and housing constitute a disposable assembly in which permanent magnets embedded in the impeller stabilize its position to maintain pumping tolerances in at least one dimension, and also couple to external fields to rotate the impeller. In one embodiment concentric arrangements of cylinder magnets passively maintain radial centering, while coils in the driver are actuated to simultaneously produce a rotational torque and to correct axial or tilt displacements. In a preferred embodiment of this type, sensors around the periphery detect axial displacement and/or tilt as the impeller turns, while the drive circuit responds to the sensor signal to produce compensating phase changes in the coil drive signals.