After prolonged exposure to cold, an elderly man was found with altered mentation by his family physical examination revealed hypothermia. The electrocardiogram demonstrated characteristic changes. Results of an extensive diagnostic workup revealed only adrenal insufficiency, and the electrocardiographic abnormalities resolved after warming. Hypothermia can result from a variety of endogenous and exogenous causes; the most common of these, however, is accidental exposure. While history and physical exam are the best means for diagnosing hypothermia, several laboratory abnormalities are typical. One finding on electrocardiogram, while not pathognomic, is highly suggestive of hypothermia: the Osborn wave. Other findings on electrocardiogram can assist in diagnosis as well, but the only factors shown to predict outcome are atrial fibrillation and shivering artifact.