From 1967 through 1976, 754 adult patients were subjected to open heart procedures for acquired valvular disease at the University of California, San Francisco, 104 of whom were 66 years of age or over (mean = 70 years). The operative mortality of 15.0% in the elderly group did not differ significantly from that of 14.3% in the entire adult series for the 10-year period. Mortality was consistently higher in combined procedures (multiple valve replacement and valve replacement with coronary grafting). Since the introduction, in 1973, of hypothermic hyperkalemic coronary washout for intraoperative protection of the ischemic myocardium, the hospital mortality rate has decreased to 8.1% overall, 6.0% for isolated aortic valve replacement and 0% for isolated mitral valve replacement in patients over 65. Moreover, the long-term survival following aortic and mitral valve replacement in this series appears to approximate the survival curve of the normal population of the same age. This experience suggests that cardiac surgery has become safer for all patients during the past 10 years and that operative mortality is related primarily to the type and severity of disease rather than to age.