Herein is reported the case of a 43-year-old woman, who experienced an acute aortic dissection associated with underlying Cushing's syndrome. The patient had central obesity and a moon face of ten years duration, but had never sought medical consultation. On the day of her presentation, she experienced a severe chest pain radiating to her back. Computed tomography revealed a Stanford type B acute aortic dissection and a left adrenal mass. From her hormonal study results, clinical symptoms and signs, she was diagnosed with Cushing's syndrome, which was due to a left adrenal adenoma. After medical treatment to stabilize the aortic dissection, she underwent left adrenalectomy. The aortic lesion of the present patient suggests that hypercortisolemia arising from Cushing's syndrome might be related to the development of acute aortic dissection.