We present our 12-year experience with surgical treatment of aneurysms of the thoracic aorta in a high-risk patient population. Of 52 patients with aneurysms, 36 patients, aged 19 to 80 years, had operation. In 24 of the 36, there were three or more associated major disease processes, such as chronic bronchitis, hypertensive cardiovascular disease, aortic valve disease, cerebrovascular disease, abdominal aortic aneurysm, and coronary artery disease. Eight patients with acute type A (ascending aorta) and seven with acute type B (descending aorta) aneurysms had emergency repair, with survival in four and seven, respectively. All patients with chronic type A or B aneurysms had elective repair, and all patients with acute or chronic type A aneurysms had surgical treatment. Four patients with acute type A and two with acute type B aneurysms had elective operation, with survival in three and one, respectively. Nine patients with chronic type A and six with chronic type B aneurysms had elective operation, and all survived. Twelve patients with chronic type B aneurysms did not have operation, and all were alive at early follow-up. Mortality for patients having acute type A aneurysms requiring emergency operation was greater than that after elective repair of acute or chronic type A aneurysms. Short-term survival for chronic type B aneurysms was similar whether the patient was treated medically or surgically.