A new tilting disc valve is described. It is a free-floating delrin disc which tilts open to an angle of 60°. The gradient is negligible and much smaller as compared with ball and non-tilting valves in the aortic area. As the disc is not overlapping, blood trauma is minimal. The heart sounds are nearly normal. No diastolic and in most cases only a minimal systolic murmur is heard. 45 cases have been followed up to 6 months. In 1969, when we have had excellent results for up to seven years with ball valve prosthesis and 3 years with disc valves (Kay-Shiley) in the aortic root, there is still an urgent need to improve the artificial valves, both as regards the haemodynamics and long term results.