Five patients with accidental hypothermia are reported. Admission rectal temperatures ranged from 24 degrees C to 31.7 degrees C and two patients had suffered circulatory arrest. Ages ranged between 25 and 77 and predisposing factors included alcoholism, gluterthimide poisoning, pancreatitis and cerebro-vascular accident. Along with respiratory and circulatory management in an intensive care unit the patients were actively rewarmed by peritoneal dialysis with fluid at 37 degrees C. Rewarming was rapid, smooth and free of complications. All five patients made a good recovery.