Five patients out of a group of 75 with advanced renal failure with evidence of tertiary hyperparathyroidism have been treated by subtotal parathyroid excision. Prior to surgery all patients were receiving chronic dialysis. Four patients developed signs and symptoms of hyperparathyroidism resistant to medical therapy in the course of dialysis, and one following transplantation of a cadaveric kidney. This latter patient also developed widespread metastatic calcifications of soft tissue and severe vascular insufficiency. Each of the five patients had 3 or 3½ parathyroid glands removed. Response to surgery was assessed by biochemical, radiological, and clinical criteria. Results ranged from poor in one patient to fair in three patients and were excellent in one.