In emergency medicine accidental hypothermia in non-traumatized patients is a rare situation. To emphasize the need for a precise preclinical temperature measurement, two cases of accidental hypothermia (28.2 degrees C and 29.3 degrees C core temperature) are presented which occurred under conditions that did not give a direct suspicion of hypothermia. In one case the immediate diagnosis lead to complete convalescence, the other patient died of multiple organ failure. The primary diagnosis, diagnostic methods and therapy as well as the primary treatment are discussed.