Abstract: Objective : To explore the incidence of complicatiom transplantation and the efficacy ofallogeneic peripheral blood stem cell transplantation (Allo-PBSCT) for chronic myeloid leukemia(CML). Methods : Seventeen CML patients, including 15 in chronic phase, 1 in accelerate phase and 1with blast crisis, were treated with Allo-PBSCT from HLA-identical (16 cases) and 2-locus mismatched(1 case) siblings. The BU/CY was used as conditioning regimen. Cyclosporine A (CsA), mycophenolatemofetil (MMF) and short ourse methotrexate (MTX) were administered to prevent GVHD. Results : Allpatients were successfully engrafted. The medium time of neutrophil count ≥0.5×10⁹/L was 11 days(range 9~13) and platelet count≥20×10⁹/L was 16 days(range 14~21). Acute GVHD occurred in 1 pa-tient (6.25%) and chronic GVHD occurred in 4 patients (25%)for HLA-identical siblings transplanta-tion, one case with 2-locus mismatched siblings transplantation occurred acute GVHD. Fifteen patientswere still alive in complete remission with a median follow-up of 19 (2~43) months and 2 died. Con-Clusion : Allo-PBSCT is a safe and effective therapy for CML and the CsA/MMF/MTX regimen for pre-vention of acute GVHD is effective.