Hypothermia usually occurs because a patient has been exposed to a cold environment; however, a number of nonenvironmental conditions may produce hypothermia. This report relates the clinical course of a patient whose hypothermia was due to severe diabetic ketoacidosis. In addition, we review the causes of hypothermia and Osborn waves beyond exposure to cold temperature. Hypothermia due to diabetic ketoacidosis is an uncommon complication of a common disease that carries with it clinically significant consequences. Accordingly, we believe that all clinicians should be aware of this potential complication of diabetic ketoacidosis and should be able to recognize the importance of the electrocardiogram in such patients.