Serum parathyroid hormone, calcium and phosphate were daily monitored in 12, 30 and 30 patients respectively during the early postoperative period after removal of a solitary parathyroid adenoma. In all patients PTH concentration dropped to very low values on the first postoperative day, whereafter a rapid recovery began. So the first day is the best time to evaluate the results of the intervention. Hypocalcemia was most frequent on the third day. After ten days 26 patients showed a normal calcemia, while 4 patients still had a mild hypocalcemia (8-8.8 mg/dl). These data may guide management of patients after parathyroid surgery.