Transfusion-related acute lung injury (TRALI) is a syndrome of sudden-onset noncardiogenic pulmonary edema occurring during or a few hours after transfusion of a blood product. TRALI is believed to occur in approximately 1 in every 5,000 transfusions and it usually occurs after administration of products containing large amounts of plasma, although it has been reported to occur after administration of as little as 50 mL of whole blood or any plasma-containing blood products including packed red blood cells and intravenous immunoglobulins. Leukoagglutination and pooling of granulocytes in the recipient’s lungs may occur, with the release of the contents of leukocyte granules that results in injury to cellular membranes, endothelial surfaces, and potentially to lung parenchyma. In most cases, leukoagglutination results in mild dyspnea, hypoxia, hypovolemia, hypotension, fever, chills, and pulmonary infiltrates within about 6 hours of transfusion and spontaneously resolves. Occasionally, more severe lung injury occurs as a result of this phenomenon and acute respiratory distress syndrome (ARDS) results. TRALI has a reported mortality rate of 5% to 8% (the third most common cause of transfusion-related mortality). Host factors such as infection, lung disease, and recent surgery may contribute to the incidence and severity of TRALI. Laboratory findings include hemoconcentration, hypoalbuminemia, and neutropenia or neutrophilia. Typically, chest radiograph reveals bilateral infiltrates.