In 61 hemodialysis patients undergoing subtotal parathyroidectomy, there was a good correlation between the preoperative serum immunoreactive parathyroid hormone value (iPTH) and the weight of parathyroid tissue removed surgically (p less than or equal to 0.001). Postoperatively, iPTH decreased rapidly from an initial mean (+/- SD) of 2,928 +/- 1,600 muleq/ml and remained at 365 +/- 296 muleq/ml at last follow-up of patients still undergoing hemodialysis (normal, less than 50 muleq/ml). Of six patients who had recurrent hyperparathyroidism (10 percent of total), three required a second subtotal parathyroidectomy. Aluminum-related osteomalacia eventually developed in six patients with bone biopsy-proven hyperparathyroidism before parathyroidectomy. Nine patients with severe fracturing bone disease and hypercalcemia preoperatively but without clear evidence of hyperparathyroidism did not show a favorable response to subtotal parathyroidectomy (high mortality within 28 months, persistence of hypercalcemia, and symptomatic bone disease). Thus, subtotal parathyroidectomy can benefit patients with clearly established severe progressive hyperparathyroidism not responsive to medical therapy but is contraindicated in patients with low iPTH values and no bone biopsy evidence of severe hyperparathyroidism.