Thirty-five patients over the age of 80 years underwent surgery for abdominal aortic aneurysm between January 1985 and December 1990. Of these, 25 had surgery for ruptured aneurysm (mortality rate 56 per cent) and ten had surgery for symptomatic or asymptomatic aneurysm (mortality rate zero). The mortality rate for patients with rupture aged over 80 years was considerably greater than that for those under 80 years of age (56 versus 36 per cent). The mortality rate in the elderly population was zero for elective surgery but in those under 80 years it was 5 per cent. During the study period a prospective analysis of all referrals with aortic aneurysm was carried out, whether or not they underwent surgery and whether or not they were admitted to hospital. The ratio of patients accepted for operation to those not accepted for operation was 92:59 (1.56:1) in the under 80-year-old age group and 12:34 (0.35:1) in those aged over 80 years.