Thirty years ago the Smeloff-Cutter double-caged ball prosthesis was developed for aortic valve replacement. Between 1967 and 1977 a total of 46 patients admitted to the University Hospital Munich underwent an isolated aortic valve replacement with the Smeloff-Cutter prosthesis. Postoperatively all patients received anticoagulation treatment with phenprocoumon (Marcumar). A retrospective follow-up of 95.6% of patients, representing 842 patient years, was completed. The corresponding actuarial survival rates after 10, 20, and 25 years were 69.1%, 47.4%, and 31.4%. The actuarial freedom rates from either valve-related complications, reoperations, or death were 72.9%, 47.4%, and 20.3%. Thromboembolism occurred in 1.41% per patient year, bleeding in 1.90%. The rates of valvular dysfunction, reoperation, and endocarditis were 1.16%, 1.16%, and 0.2% per patient-year. Today, of the surviving patients 81% are in NYHA Class I or II, 19% in NYHA Class III. No surviving patient deteriorated over the reported time in his or her functional NYHA classification. After 25 years the Smeloff-Cutter valve has proved to be a reliable prosthesis for aortic valve replacement and-together with the Starr-Edwards prosthesis-it has set a standard in longterm durability by which all other valve designs will have to be measured.