A case of left adrenal adenoma with bilateral testicular Leydig cell tumor in a 38-year-old man is reported. He had received bilateral orchiectomy for testicular Leydig cell tumor at the age of 37. After operation computed tomography revealed left adrenal mass and aldosterone-secreting adrenal tumor was suspected. Left adrenalectomy was performed and histopathological diagnosis was adrenocortical adenoma. Serum ACTH, aldosterone and plasma renin activity were still high after operation. The adrenal cortex and gonads are of common embryologic origin and the histologic pattern may overlap. Examination of the adrenal gland is necessary for the patient with a testicular Leydig cell tumor.