Severe hypothermia may lead to hypo- or hyperglycaemia. We report two cases of the latter, less common, condition in which the blood glucose levels were 638 and 580 mg/l00 ml. The glucose levels in both cases fell rapidly on rewarming, without any exogenous insulin and despite one patient being an insulin-requiring diabetic. The glycaemic status in hypothermia appears to result from the relative contributions of reduced hepatic glucose production, leading to hypoglycaemia and reduced glucose uptake by the liver and peripheral tissues, causing hyperglycaemia. Rewarming alone appears to normalise glucose homeostasis by facilitating glucose utilisation.S. Afr. Med. J., 48, 1617 (1974)