Two women aged 51 and 52 years old, respectively, developed a brain infarction before and after undergoing treatment for Cushing's disease. A biochemical remission was obtained more than ten years after the onset of signs or symptoms of Cushing's disease. The arteriosclerotic changes of the cerebral vessels progressed even during replacement therapy for posttreatment hypopituitarism after they underwent either ablative surgery or radiotherapy. One patient, who showed the signs of Nelson's syndrome, demonstrated severe progressive cerebrovascular sclerotic changes, especially around the irradiated site. It is thus suggested that hypercortisolemia, external pituitary irradiation, and posttreatment hypopituitarism may be risk factors for brain infarction. The early diagnosis and adequate treatment are therefore important to prevent cerebrovascular complications in patients with Cushing's disease.