Among 1,488 patients with arteriosclerotic aneurysms of the abdominal aorta and its peripheral branches seen at the University of Michigan Medical Center from 1960 to 1971, 57 (3.9%) had multiple arteriosclerotic aneurysms. Multiple aneurysms occurred in 83% of patients who had at least one peripheral aneurysm. Among the 37 patients with a common femoral aneurysm, 95% had a second aneurysm, 92% had an aorto-iliac aneurysm, and 59% had bilateral femoral aneurysms. Among the 36 patients with a popliteal aneurysm, 78% had a second aneurysm, 64% had an aorto-iliac aneurysm, and 47% had bilateral popliteal aneurysms. The importance of suspecting a nonpalpable aorto-iliac aneurysm in the presence of a peripheral aneurysm, and the usefulness of arteriography are emphasized. Planned staged resection and careful followup are required to manage these patients successfully.