The rare hungry bone syndrome was encountered in a 15-year-old child after the removal of a parathyroid adenoma. Contrary to the hypocalcemias caused by the removal of all parathyroid glands or transient ischemia after parathyroid surgery, in which the serum inorganic phosphorus level is usually normal, both serum calcium and inorganic phosphorus levels are decreased in hungry bone syndrome in the early postoperative period. Vigorous calcium supplementation and vitamin D are required for prolonged periods.