Surgery is indicated in cases of therapy-resistant reactive renal hyperparathyroidism with clinical symptoms and signs. The method of choice is total parathyroidectomy, with autotransplantation of parathyroid tissue into the forearm musculature. Twenty-two patients were parathyroidectomized. In 19 cases the intraoperative selection of tissue for autotransplantation was made by means of a stereoscopic magnifying glass. With one exception, only fragments of type 1a glands and type 1a-like areas obtained from type 2 glands were transplanted. In 18 of the 22 cases parathyroid hormone levels decreased from 1131 +/- 657 preoperatively to 87 +/- 53 pg/ml postoperatively. In 4 patients with postoperative values over 200 pg/ml a transplant-related recurrence of hyperparathyroidism or a remaining 5th gland in the cervical region was suspected. In all 22 patients serum calcium, as well as alkaline phosphatase levels returned to normal and the clinical signs of hyperparathyroidism disappeared.