Transfusion-related acute lung injury and transfusion-associated circulatory overload are characterized by acute pulmonary edema within 6 hours of blood transfusion. Despite recognition as the leading causes of transfusion-related mortality, they remain difficult to study due to underrecognition and nonspecific diagnostic criteria. Recent study has shown that inflammatory cytokines and cardiopulmonary biomarker may be useful in differentiating pulmonary transfusion reactions and furthering our understanding of their pathogenesis. It is clear that donor / component mitigation and patient blood management strategies have decreased the incidence of pulmonary transfusion reactions. Additional clinical and translational research focused on identifying at-risk transfusion recipients is needed to further prevent these frequently severe cardiopulmonary events.