In a 1980 review of the natural history and treatment of 176 thoracic aortic aneurysms, we noted the high incidence of rupture (47% overall) in 135 patients not treated surgically. Since that original study we have added another 84 patients to our series and have noted a complete change in management such that most patients are now treated surgically. We now have 260 patients in our series, 126 of whom were treated surgically. Sixty-seven were emergency operations and 59 were elective. Surgical mortality was 8% for elective resection and 33% for emergency operation. Over the past 5 years these figures have improved to 5% surgical mortality for elective resection and 16% surgical mortality for emergency resection. The 5 year survival rates for the entire series were 50% for patients treated with elective operation, 30% for combined emergency and elective operation groups, and 21% for nonsurgically treated patients. Abdominal aortic aneurysm was present in 74 patients (28%) and 23 of these patients had undergone a prior resection of an abdominal aortic aneurysm. This series documents the improved survival of patients with aneurysms of the thoracic aorta who are treated with prompt surgical intervention. It also further substantiates earlier findings of a high incidence of aneurysms of the abdominal aorta in this patient population.