A case of a pheochromocytoma in the right adrenal gland and adrenocortical adenoma in the left adrenal gland of a 58-year-old male is reported. The patient was incidentally found to have a right adrenal tumor by ultrasonographic study. A computerized tomographic (CT) study and magnetic resonance image (MRI) study revealed bilateral adrenal tumors. The sizes of the right tumor and left tumor were 2.5 x 3.5 cm and 1.2 x 1.0 cm, respectively. The intensity of each tumor was different on T2-weighted MRI. 131I-MIBG scintigram showed the uptake of right adrenal gland. The existence of pheochromocytoma was confirmed by the elevated levels of catecholamines. We performed venous sampling to be certain whether the patient had unilateral or bilateral pheochromocytoma. As a result, bilateral adrenal pheochromocytoma was diagnosed. Therefore, we performed bilateral adrenalectomy. However, histopathological examination revealed right pheochromocytoma and left non-functioning adrenocortical adenoma.