Follow-up information was obtained for 1,127 patients having had isolated aortic valve replacement between May, 1963 and April, 1976. The mean follow-up period was 4.4 years. Valves employed included Starr-Edwards Models 1000 (83 patients), 1200 (203 patients), 1260 (435 patients), and 2320 (52 patients), as well as homograft valves (103 patients) and porcine xenograft valves (251 patients). The over-all mortality rate was 7.6 percent, and the linear attrition rate thereafter was 2.7 percent per year. Long-term survival was found to be significantly related to the following preoperative variables: age, congestive heart failure, functional class, radiographic cardiac enlargement, history of acute or remote myocardial infarction, valvular lesion, left atrial mean pressure, pulmonary artery mean pressure, coronary artery disease, left ventricular angiogram, and cardiac index. From this analysis, we conclude that aortic valve replacement in asymptomatic severe aortic regurgitation, (AR) is indicated. Actuarial analysis of prosthetic valve-related death and complications suggest that the porcine xenograft valve is an excellent choice for aortic valve replacement.