Among the transfusion reaction, the hemolytic reaction due to mismatched blood transfusion is a fatal complication. After immediate fatal disaster, the renal complication is still life threatening and so its prevention and management are very important. We experienced five cases of acute renal failure and, two of five patients were developed at the SNU hospital and the remainders were transfered to the SNU hospital from local hospital. Two of five patients were showed oliguric renal failures and the remamders were showed non-o-liguric renal failures. All five patients were discharged without complication. We summerize the labaratory data of the five patients during hospitalization and together reviewed with the literatures.