The prophylaxis and treatment of renal osteodystrophy are based on pathophysiological principles. Development of secondary hyperparathyroidism should be averted by early prevention of hyperphosphatemia through diet and phosphate ligants, and by normalization of the calcium balance through calcium supplements and vitamin D or its analogues. This treatment requires close clinical and laboratory control in order to avoid several hazards (hypercalcemia, hypophosphatemia, and refractory constipation). In cases with severe secondary hyperparathyroidism, subtotal parathyroidectomy is sometimes required. Nevertheless, in one such case this operation resulted in sudden hypoparathyroidism two years postoperatively.