TRALI is a rare but serious complication associated with transfusion, and known to occur following infusion of all types of plasma-containing blood products. However, only one adult case of TRALI after allogenic marrow graft has been reported. In this study, we present a pediatric case possibly associated with allogenic marrow infusion. A 10-yr-old girl was referred to our hospital for the treatment of acute myeloid leukemia. She underwent allogenic bone marrow transplantation from her HLA-2-loci-mismatched mother. During conditioning, she suffered from bacterial sepsis, but it had improved with antibiotics until day 0 of transplantation. Two h after starting the marrow infusion, she developed severe hypoxia. We discontinued the infusion and started steroids, which improved her respiratory condition. However, she developed respiratory failure again after resuming infusion of the graft. Despite intensive care with mechanical ventilation, the patient died of endotoxin shock five days after transplantation. Although we could not identify the antibody which might have been involved in the respiratory distress, the clear temporal relationship between marrow infusion and respiratory distress suggested that similar acute lung injury to TRALI might have occurred following allogenic marrow infusion in the present case.