The term transfusion-related acute lung injury (TRALI) was coined in 1983 to describe a constellation of clinical and laboratory features seen within 6 hrs of the transfusion of plasma-containing blood products. These products contain antibodies directed to human leukocyte antigens (and subsequently described to nonhuman leukocyte antigens) found on white blood cells. In the intervening 2 decades, other cases not associated with antibodies have been reported as TRALI and an association with passive infusion of lipids accumulated in stored cellular blood products has been made in those cases. This has led to confusion as to what should be considered to constitute TRALI. Therefore, the true incidence of this pulmonary reaction to blood products is currently conjectural at best. Recent consensus development conferences have been held to develop and standardize definitions of TRALI so that epidemiologic and research aspects of this condition can be explored in a scientific manner. These conferences have set out criteria by which TRALI is distinguished from other causes of acute lung injury. This review outlines the widely accepted clinical (mainly pulmonary) features of TRALI, the treatment options, and the excellent long-term prognosis for patients who survive the initial pulmonary insult.