The physiologic changes produced by hypothermia include impairments in the stress response and immune system, and drug clearance, exacerbation of lactic acidosis, cardiac arrhythmias, and coagulopathies. Transfusion with cold blood is known to produce profound changes in body temperature and other metabolic responses with significant morbidity especially in infants and children. Warming blood for transfusion has been a common practice to avoid the dangers of hypothermia following cold blood transfusion. However, overheating of packed red blood cells results in hemolysis and transfusion of hemolyzed blood may cause hypotension, shock, and renal dysfunction. This case report describes an acute hemolysis due to transfusion of overheated blood.