229 patients aged 70 or over with aortic stenosis (AS) underwent surgery between January 1972 and July 1983 (21.8% of 814 cases of AS operated on during the same period). The Björk Shiley prosthesis was used at the beginning of the series (115 cases, 50.2%), until bioprostheses became the treatment of choice in this age group. Overall operative mortality in the series was 10.9% (25/229). Analysis shows a very marked reduction in recent years: from 15.6% between 1972 and 1977, to 5.8% in 1982-3. Improvement can be attributed in part to the technical progress in myocardial protection. Patient age is a very significant factor in the prognosis. Progress in surgery, together with that in anaesthetics and intensive care, justifies operation in these elderly and incapacitated patients whose general and neurological condition is well preserved.