During the period 1971-1976, subtotal parathyroidectomy was performed on 34 patients with chronic renal failure, representing 8% of all uraemic patients treated on the Renal Ward. Preoperative treatment of renal failure was conservative therapy in 6, haemodialysis in 20 and renal transplantation in 8 patients. The operation was indicated by grave clinical symptoms (pruritus, bone pains and mental disturbances), gastric ulcer and radiological abnormalities (osteoporosis, fractures, subperiosteal resorption and metastatic calcifications). The serum immunoreactive parathyroid hormone was determined in 13 cases, and the value was elevated in all. The serum calcium level was elevated in 8 out of 34 cases. Less than 500 mg of parathyroid tissue was removed in 12 cases, between 500 and 6000 mg in 19 and over 6000 mg in 3. Nodular hyperplasia was present in 11 patients, diffuse hyperplasia in 23. Postoperatively marked falls in serum parathyroid hormone and serum calcium values were observed. The bone pains, pruritus and mental disturbances were alleviated, and the general condition was favourably influenced. The operation had a lesser and more retarded effect on the radiological changes. Complete recovery was only achieved with successful renal transplant. Parathyroidectomy often had a favourable effect on the grave symptoms and may, therefore, be considered in some cases of severe hyperparathyroidism secondary to chronic renal failure.