It has been clearly shown clinically that parathyroid tissue can be successfully autotransplanted and even allotransplanted if the host is immunosuppressed. Engraftment is almost always successful; however, if abnormal tissue has been transplanted, its function will continue to be abnormal if the same intrinsic (e.g., primary parathyroid hyperplasia) or extrinsic (renal osteodystrophy) stimulation existing before grafting continues in the postoperative period. In these patients the secretion of parathyroid hormone from the grafted parathyroid tissue can be shown to progressively increase with time. Although parathyroid autotransplantation is most frequently performed clinically for renal osteodystrophy, there is controversy about the operation, and some surgeons prefer the technique of 3 1/2 gland parathyroidectomy. Because of the generally good results with total parathyroidectomy and autotransplantation in patients with primary parathyroid hyperplasia, this procedure seems to be the operation of choice in this clinical setting. The clearest indication for parathyroid autotransplantation is in patients with radical operations on the thyroid gland or other head and neck organs where the parathyroids have been damaged or their viability is questioned.