Because of the significant reduction in complications from transfusion owing to the development in the technique of preservation of blood, the tendency of hemoglobinuria during anesthesia and surgery has decreased. it seems that there are many causes of hemoglobinuria, and its prognosis is varied. The incidence of Rb negative blood in Korea is no more than 0.2%. Therefore, such a rare blood type may be presserved by freesing for longterm storage. But this freesing and thawing of blood leads to partial hemolysis of the red cells. A case of hemoglobinuria occured during transfusion of Rh negative type B frozen blood.