Between 1978 and 1987, 587 cases of abdominal aortic aneurysm were operated on in the Vascular Unit of the Royal Infirmary of Edinburgh. Over this ten-year period there was a dramatic increase in the number of patients treated. Rupture had occurred in 278 patients. Of the 309 patients with non-ruptured aneurysm 175 were asymptomatic, 84 were symptomatic and 50 were acutely symptomatic. Two hundred and fifty-nine patients underwent elective operation and the 50 acutely symptomatic patients were operated on as emergencies. The overall mortality for the non-ruptured series was 2·9 per cent. The mortality in patients undergoing elective surgery was 1·9 per cent (1·1 per cent in asymptomatic and 3·6 per cent in symptomatic patients) and 4·0 per cent for patients undergoing emergency surgery.