Management of the hypothermic patient concerns physicians in many specialties. Accidental hypothermia is commonly encountered in the emergency and operating rooms and in the adult and neonatal intensive care units. Intentional induction of hypothermia is used routinely in cardiac surgery to reduce total body metabolism and oxygen consumption, which is beneficial when an increased tolerance to ischemia is required, such as during total circulatory arrest. Hypothermia is associated with such complications as acidosis, impaired myocardial function, altered blood clotting, decreased kidney and liver function, and intracellular swelling. This review summarizes the laboratory, theoretical, and clinical evidence that the management of blood pH during hypothermia may alter the appearance or magnitude of these deleterious effects.