An improved trileaflet mechanical heart valve 100 can include an improved leaflet 110. The valve 100 and leaflet 110 provide improved flow characteristics, minimize blood clotting behind the leaflets, and provide more natural opening and closing times. The valve can include a valve housing 105 which contains pivot/hinge mechanism (130, 200, and 300) for allowing rotation of and retention of the leaflets 110. The valve housing 105 can also include windows or openings 125 which allows for complete washing of the pivot/hinge mechanism (130, 200, and 300) as well as the leaflets 110. The novel leaflets 110 are airfoil-like having a complex S-shaped curvature on their outer surface. This novel geometry, when combined with the location of the leaflet's pivot axis, causes a tendency for the leaflets 110 to rotate towards the closed position. Thus, the leaflets 110 begin to close much earlier than a conventional leaflet and are substantially closed before the flow reverses, similar to the function of a natural valve.