Accidental hypothermia is defined as an environmentally induced reduction of the core body temperature to 35 degrees C or below, where there is no primary endocrine or preoptic anterior hypothalmic dysfunction. We report a survivor of 12 episodes of accidental hypothermia. A comparison of his rewarming rates with passive external versus active core rewarming by inhalation of heated humidified oxygen via nasotracheal tube is provided. Multiple predisposing factors contributed to the repeated episodes of hypothermia. Anatomic causes of repeated nonaccidental hypothermia were excluded.