Cushing's syndrome and Cushing's disease cause various metabolic disorders associated with high cortisol levels. Some reports have shown that Cushing's syndrome is complicated with dissecting aortic aneurysm and aortic dissection after long-term exposure to high cortisol levels. We herein report a rare case of aortic dissection complicated with Cushing's disease. Aortic dissection may occur even under relatively short periods of high cortisol conditions. This case suggests that hypercortisolemia should be treated as soon as possible in order to prevent aortic dissection in subjects with Cushing's disease.