A 23-year-old woman who had undergone total thyroidectomy and parabronchial lymphadenectomy at the Department of Otolaryngology in our hospital was suspected to have a thyroid carcinoma. Histological examination revealed a medullary carcinoma of the thyroid and normal parathyroid glands. Because a computed tomographic scan after surgery revealed a tumor of the left adrenal gland, the patient was examined at our department two months after the thyroidectomy, 1994. Endocrinic examinations and 123I-MIBG scintigraphy revealed a left adrenal pheochromocytoma of Sipple syndrome. She then underwent left adrenalectomy. Histological diagnosis was pheochromocytoma of the left adrenal gland. Three years after the surgery, a right adrenal tumor was detected by computed tomography. Although results of endocrine examinations were normal, 131I-MIBG scintigraphy showed a hot spot in the right adrenal gland. Right adrenal pheochromocytoma was diagnosed 3 years after surgery for a contralateral adrenal pheochromocytoma. Although surgery was recommended, the patient consented to right adrenalectomy, 1 year later after marriage and before becoming pregnant. Histological examination of the resected specimen revealed pheochromocytoma of the right adrenal gland.