To know the characteristics of mortality from aortic aneurysms in Japan, the age-adjusted and age-specific mortality rates of the diseases were calculated based on the Vital Statistics of Japan published from the Statistics and Information Department, Minister's Secretariat, Ministry of Health and Welfare. The overall age-adjusted mortality rate increased 24.8-fold from 0.43 to 10.98 per 100, 000 for males, and 18.6-fold from 0.23 to 4.54 per 100, 000 for females from 1955-90. The most common type was abdominal aortic aneurysms followed by dissecting and thoracic aortic aneurysms. The mortality rates of dissecting and thoracic aortic aneurysms increased greater than that of abdominal aortic aneurysms. The mortality rate of dissecting aneurysms was higher than that of abdominal and thoracic aortic aneurysms in age groups of 64 years or under. The mortality rate of abdominal aortic aneurysms was the most common in age groups of 65 years or over. © 1993, Tohoku University Medical Press. All rights reserved.