A 22-year-old man eventually had a good neurologic recovery following prolonged coma after extracorporeal rewarming from profound hypothermia (24 degrees C) due to exposure. The patient was in full arrest for 60 minutes prior to institution of cardiopulmonary bypass (CPB). Total bypass time was 50 minutes. Cardiopulmonary bypass is the current rewarming method of choice for severe hypothermia associated with a persistent nonperfusing cardiac rhythm. CPB provides the most rapid core rewarming with the additional benefit of circulatory support during the period of cardiac instability.