OBJECTIVE The purpose of this review is to provide an overview of concepts recently presented in the literature that impact our understanding of transfusion related acute lung injury (TRALI) and transfusion associated circulatory overload (TACO), and how to distinguish between the two disorders. RESULTS An exceptionally clear review article by Brux and Sachs clarified the two-hit model of TRALI pathogenesis. The TRALI definition developed at the 2004 consensus conference helped demonstrate that TRALI is likely underreported. Brain natriuretic peptide can be useful in distinguishing cardiogenic from noncardiogenic pulmonary edema. Blood centers are implementing male predominant plasma programs to limit TRALI, and preliminary evidence suggests that this is a useful intervention. CONCLUSIONS TACO and TRALI have emerged as important causes of posttransfusion morbidity and mortality. As understanding of their pathogenesis improves, incidence, risk factors, differences, and possible preventive interventions are becoming clearer. There is no sentinel feature that distinguishes TRALI from TACO. Developing a thorough clinical profile including presenting signs and symptoms, fluid status, cardiac status including measurement of brain natriuretic peptide, and leukocyte antibody testing is the best strategy currently available to distinguish the two disorders.