Four patients with end-stage renal failure on intermittent hemodialysis in whom rhabdomyolysis developed after major surgery are described. This possibly underdiagnosed complication was manifested by extreme hyperphosphatemia, hypocalcemia, and elevated creatine phosphokinase levels. Serum myoglobin levels further supported the diagnosis. The metabolic abnormalities reached a peak on the fourth postoperative day. The possible precipitating factors included opiates used for anesthesia and postoperative pain central, anesthetic agents, and surgical position. The preferred treatment option is increasing dialysis to control hyperphosphatemia and hypocalcemia. (C) 1998 by the National Kidney Foundation, Inc.