Abstract： Objective To investigate the efficacy of allogeneic peripheral blood stem cell transplantation (PBSCT) in the treatment of severe aplastic anemia (SAA) and severe infection. Methods A patient with SAA and pseudomonas aeruginosa septicemia was treated with PBSCT from an HLA-identical sibling with cyclophosphamide (CY) and total body irradiation (TBI) for conditioning. The patient was infused with 20.3×108/kg mononuclear cells including 61.0×106/kg CD34+cells following the conditioning regimen. Results Twenty days after PBSCT, the absolute neutrophil count (ANC) of 1.0×109/L was achieved, with platelet count >50×109/L. The donor origin of engraftment was confirmed by polymerase chain reaction (PCR) analysis of short tandem repeats at the end of the first, sixth and twelfth month. The patient's body temperature dropped to normal level when her ANC reached 0.5×109/L on day 10, and the bacterial culture of blood sample became negative subsequently. Symptoms and signs of acute or chronic graft versus host disease (GVHD) were not observed in 30 months after PBSCT. Conclusions Hematopoiesis was reconstituted shortly after PBSCT. The combination of CY and TBI and the infusion of sufficient peripheral blood stem cells may contribute to the successful engraftment. PBSCT may be considered as the first choice when hematopoietic stem cell transplantation is needed for SAA patients complicated with severe infection.