A review was given of a 15 yr experience of valve replacement with Teflon cusps, pericardial cusps, Starr-Edwards, Key-Shiley, Wada-Cutter and Bjork-Shiley artificial valve prosthesis. The Bjork-Shiley tilting disc valves showed the lowest gradient and blood trauma and excellent durability in more than 1000 implantations during a 7 yr period. Anticoagulation therapy is considered necessary with all types of artificial heart valves. Thrombo-embolism was negligible after aortic valve replacement (1 episode in 4000 patient mo.) but still a problem in the mitral position (4 episodes in 1000 patient mo.).