A review of 1,510 patients treated for aortic aneurysms at all levels found that 191 (12.6%) had multiple ones. More than half of those with thoracic aneurysms had other lesions, and 12% of those with abdominal aneurysms had thoracic aneurysms. Abdominal lesions were the most common secondary lesions in the former group. Early results of treatment varied with method: 90% survived when both aneurysms were treated at one operation; 84%, when operations were staged; and 80% when operation was limited to symptomatic lesions. Most of the early deaths in the latter two groups were caused by rupture of the second aneurysm. Long-term survival was much better in patients with complete treatment. Aortic aneurysmal disease is multifocal and needs total aortic screening for diagnosis; best results are obtained by complete replacement of all disease.