From 1986 to 1996, 237 patients underwent surgical treatment of thoracic aorta in our institute. We classified them as follows: group 1 is 41 patients older than 75: group 2 is 196 patients younger than 74. The number of patients of elective surgery, emergent surgery for acute dissection type A and emergent surgery for rupture or impending rupture were 28, 9, 4 in group 1 and 123, 47, 26 in group 2. Operative death (within 30 days) of elective surgery, emergent surgery for acute dissection type A and emergent surgery for rupture or impending rupture were 1 (3.6%, MOF), 1 (11%, liver failure), 2 (50%, brain damage) in group 1 and 8 (6.5), 3 (6.4%), 9 (35%) in group 2, respectively. Hospital deaths (after 30 days and cannot discharge) were 3 (11%), 0.1 (25%) in group 1 and 3 (2.4%), 1 (2.1%), 1 (3.8%) in group 2. There was no significant difference between two groups. Survival rate of each group were 48% and 80% for five-year survival rate. Complications in elderly patients were common (88%). Respiratory insufficiency is the most frequent (51%). Otherwise survival rate of patients who had no surgical treatment of diseased thoracic aorta was reported poor by several researches. We will perform operation for elderly patients positively if we can get agreement of patients.