Werner syndrome is a rare genetic disease characterized by progeria, diabetes mellitus, cataracts and various types of malignancy. However, there are few reports showing adrenal cortex cancer in subjects with Werner syndrome. We herein report an extremely rare case of Werner syndrome accompanied by adrenal cortex cancer. Based on the data obtained from blood samples, computed tomography, magnetic resonance imaging and 131I adosterol scintigraphy, we diagnosed this subject with adrenal cortex cancer and Cushing's syndrome. Since the prognosis of adrenal cancer is very poor, we should be aware of the possibility of adrenal cancer occurring in subjects with Werner syndrome.