From 1971 to 1985, 355 patients over 70 years of age (mean age 73.7) underwent isolated aortic valve replacement, most of them for pure calcified stenosis (78.6%). Mechanical valves (group A) were used in 112 cases (109 Bjork-Shiley; 3 SJM) and bioprostheses (group B) exclusively implanted since 1981 (192 Edwards-Carpentier; 51 Ionescu-Shiley). Thirty-six patients died post-operatively (10.1%). 36% of the deaths were related to cardiac causes, and 14% to cerebral damage. The follow-up involved 100% of the 319 survivors and spanned 12 years (1 month to 11.8 years), with an average of 3.2 years. The follow-up was almost equally distributed between groups A and B: 474 and 453 patient-years, respectively. Sixty late deaths (18.8%) occurred: 26.7% of them related to cardiac causes, and 20% to cerebral accidents. Twenty-nine cases were in group A (6.1% patient-years), and 31 in group B (5.7% patient-years). Acturial analysis shows that, at five years, 94.1% of patients in group A and 96% in group B were free of valve-related complications, and that 88.9% in group A and 89% in group B were free of valve-related non-lethal complications. Actuarial calculation of survival rates shows that, at five years, the probability of survival was 70.8% for the entire series, including the operative deaths. This curve of survival is similar to that of the normal population of the same age. Moreover, the functional status is dramatically improved by surgery: 99.6% of patients are in the NYHA classes I or II.