Abstract: A heart valve prosthesis has an annular valve body and two curved leaflets which are pivotally mounted for movement between open and closed positions. A 360.degree. groove is provided in the interior surface of the valve body, and spherical pivots projecting from opposite sides of the leaflets are pivotally received in the groove. The valve functions as a check valve, and the flow reversal which occurs during the pumping strokes of the heart causes the leaflets to pivot from one position to the other. As the leaflets pivot, they orbit about the axis of the valve eliminating localized wear which could otherwise occur at the locations in the valve body against which the rotating pivots would bear.