Transfusions of blood and blood products are live-saving, but complications may be fatal. Transfusion related lung injury (TRALI) is rare and pathophysiology not yet entirely understood. Diagnosis is difficult due to the usually life-threatening circumstances associated with transfusions and underlying diseases. In this mini-review article, we introduce two cases of TRALI to discuss the problems and controversies associated with different definitions, epidemiology, pathophysiology, blood products, diagnosis, and treatment. Future directions in the field are highlighted.