Abstract： Objective To explore the clinical outcome of HLA haploidentical vs HLA-matcbed peripheral blood hematopoietic stem cell transplantation (PBSCT) without in vitro T-cell depletion for malignant hematological diseases. Methods 111 patients with malignant hematological diseases underwent PBSCT without in vitro T-cell depletion between May 2004 and February 2009, including 51 patients with HLA-haploidentical and 60 patients with HLA-matched. All patients have received myeloablative conditioning regimen. A two-agent based graft-versus-host disease (GVHD) prophylaxis was used as cyclosporine A and a short course of methotrexate. Mycophenolate mofetile was added for the patients with one locus mismatch. Mycophenolate mofetile, antithymocyte globulin and CD25 monoclonal antibody were added for the patients with 2-3 loci mismatch. The grafts were granulocyte colony-stimulating factor-mobilized peripheral blood stem cells without in vitro T-cell depletion. Results 111 patients achieved sustained and full donor-type engraftment. The median time to reach an absolute neutrophil count above 0.5×10~9/L was 14 days and that to a platelet count exceeding 20×10~9/L was 15 days in 51 HLA-haploidentical patients, and that was 12 days and 13 days in 60 HLA-matched patients, respectively. In 51 HLA-haploidentical patients, 25 patients developed aGVHD, including 20 cases of grade Ⅰ aGVHD, and 5 cases of grade Ⅱ. Thirty-three patients developed cGVHD with limited in 30 and extensive in 3. The 4-year cumulative incidence of cGVHD was 70.4 %. The 3-year probabilities of leukemia-free survival (LFS) were 74.5% (77.3 % for standard risk patients and 68.2 % for high risk patients respectively). Seven patients had recurrence. In 60 HLA-matched patients, 14 patients developed aGVHD, including 10 cases of grade Ⅰ, 2 cases of grade Ⅱ and 2 cases of grade Ⅲ. Thirty-seven patients developed cGVHD with limited in 32 and extensive in 5. The 4-year cumulative incidence of cGVHD was 58.1%. The 3-year probabilities of LFS were 72.1% (77.6 % for standard risk patients and 52.7 % for high risk patients respectively). Ten patients had recurrence. The incidence of aGVHD in HLA-haploidentical cohort was significantly higher than in HLA-matched cohort (P<0.05). There was no significant difference in incidence of cGVHD, incidence of relapse and LFS between HLA-haploidentical and HLA-matched cohorts (P>0.05). Conclusion Haploidentical PBSCT is feasible and safe for malignant hematological diseases to use myeloablative conditioning regimen in combination with intensive immunosuppressants without in vitro T cell depletion.