A 56-year-old woman who was undergoing dialysis for renal failure that occurred 4 years previously was identified with hypercalcemia and high levels of intact parathyroid hormone (iPTH), as observed on blood analysis results. Blood analysis also indicated high levels of Ca (12.7 mg/dL) and parathyroid hormone (PTH 1,280 ng/mL). Secondary hyperparathyroidism was suspected to be the cause of hypercalcemia. Cervical neck ultrasonography revealed a 13-× 4-mm hypoechoic mass in the lower left pole of the thyroid gland. Tc-99 metaiodobenzylguanidine (MIBG )imaging revealed aberrant accumulation at the lower region of the left accessory thyroid. Cervical neck computed tomography revealed a 12-mm mass at the inferior pole of the left thyroid gland. Considering the above observations, a diagnosis of lower left parathyroid adenoma was made. Lumpectomy was performed, and the final pathology report indicated oxyphilic adenoma. Chief cells are often observed in parathyroid adenoma, but, to our knowledge, this is the first case of a parathyroid adenoma with oxyphil cells.