Transfusion-related acute lung injury (TRALI), a previously ill-defined transfusion reaction, has emerged as the leading cause of transfusion-related morbidity and mortality reported to the Food and Drug Administration (FDA). A 3-year-old male with a history of acute lymphoblastic leukemia (ALL) developed TRALI after receiving three units of platelets and a partial unit of packed red cells. He recovered after 24 hours in the pediatric intensive care unit. Laboratory investigation revealed that two of the four blood donors, from which the platelets and packed red cells had derived, had positive human leukocyte antigen (HLA) antibody screens. Further testing of these two donors revealed that one had a specific HLA antibody matching an antigen of the patient. This donor was implicated in the TRALI reaction. TRALI is often mistaken for other transfusion reactions, most notably pulmonary edema caused by circulatory overload or congestive heart failure. It is difficult to gauge which transfusion recipients are at risk for TRALI. Good judgment and transfusion practices when ordering blood products and recognition of the clinical manifestations, diagnosis and treatment of TRALI is critical.