This study was aimed to explore the efficacy and associated complications of haploidentical peripheral blood stem cell transplantation (hi-PBSCT) without ex vivo T-cell depletion in treatment of hematological malignancies. 15 high-risk patients received HLA 1-3 loci (A, B, or DRB1) mismatched hi-PBSCT. The modified Bu/Cy or TBI/Cy regimen was used for preconditioning of patients. The anti-thymocyte globulin, cyclosporin A, methotrexate and mycophenolate mofetil were used for GVHD prophylaxis. 4 cases were administrated with anti-CD25 monoclonal antibody. G-CSF-mobilized peripheral blood stem cells were infused, with the median number of infused nucleated cells was 8.16 (3.92-10.86)x10(8)/kg and that of CD34+ cells was 4.51 (1.27-5.95)x10(6)/kg. The results showed that the rapid engraftment was observed in all cases. The median times of neutrophil recovery>or=0.5x10(9)/L and platelet recovery>or=20x10(9)/L were 14 (11-19) and 22 (11-52) days after transplantation respectively. 6 cases developed acute GVHD of grade I-II, and 2 cases experienced chronic extensive GVHD. Infection within 100 days after hi-PBSCT was documented in all cases. 8 cases were subjected to bacterial infection, and six got cytomegalovirus infection. Relapse occurred in five cases. Overall survival of patients was 46.7% (7/15), with a median follow-up of 213 (42-589) days. In conclusion, hi-PBSCT provides an effective alternative treatment for high-risk patients in lack of matched donors, and to reduce the high transplantation-related mortality.