We reviewed the clinical features, laboratory findings, and skeletal abnormalities of six patients who have been on dialysis therapy for 12 to 20 years (average, 16.7 years), Hemodialysis has been the major therapeutic modality in five of the six individuals, Ages of the patients ranged from 28 to 67 years (mean, 44.5), Bone biopsy specimens were available for five of the patients. in three of these, the predominant changes in bone were those of osteitis fibrosa. In two patients with severe osteitis fibrosa, there was a decrease in height, Two patients had predominantly osteomalacia, but in one of these, the condition was noted before the initiation of 13 years of chronic ambulatory peritoneal dialysis, supplanted 2 years ago by hemodialysis, Total parathyroidectomies with implants of parathyroid tissue in the forearm were performed in four of the six patients, All four had, and continue to have, markedly elevated levels of parathyroid hormone (PTH). Symptoms and signs of amyloidosis of bone have occurred in all six patients, including carpal tunnel syndrome in two, bane cysts in three, and presumptive tendon involvement of the shoulder in one patient, The pathogenesis of hyperparathyroidism is described briefly, and appropriate treatment is summarized. (C) 1996 by the National Kidney Foundation, Inc.