Transfusion associated acute lung injury (TRALI) is an infrequent but hazardous complication of transfusion. This syndrome is characterized by symptoms of acute respiratory distress and clinically evident noncardiogenic pulmonary edema. The occurrence of this entity is linked to the circulating leukoagglutinins. However many reports showed the incidence of this syndrome around 0.01% per unit transfusion, only three cases whose diagnosis were considered as TRALI were reported in Japan. It is because this syndrome was often misdiagnosed as other diseases, including cardiogenenic pulmonary edema or pneumonia. Some reports showed that the implicated donors were multiparous females. In an effort to prevent this syndrome, blood collection centers should limit component usage from multiparous donors to washed red cells.