We have developed the Valvo-Pump, an axial flow blood pump, which is implanted at the natural heart valve position. This device has several advantages; it fits well anatomically, its blood-contacting surface is small because the left or right ventricular cavity is used as the blood storage reservoir, and it is implanted as easily as an artificial heart valve replacement. The Valvo-Pump consists of an impeller and a motor, both of which are encased in a housing. An impeller with 5 vanes (22.0 mm in diameter) is connected to a samarium-cobalt-rare earth magnet direct current (DC) brushless motor (21.3 mm in diameter and 24.9-mm-long). Sealing is achieved by means of a ferro-fluidic seal. A pump flow of 16.11/min was obtained at a pump differential pressure of 7.7kPa (58mmHg), and a flow of 5.01/min at 18.4kPa (138mmHg) with a motor speed of 8500 revolutions per min (rpm). Sealing was kept perfect against a pressure of 29.3 kPa (220 mmHg) at 9000 rpm. The Valvo-Pump is a very promising and simple method of circulatory support.