This study was purposed to explore the efficacy of hematopoietic reconstitution and survival of patients with myelodysplastic syndrome (MDS) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Allo-HSCT without T lymphocyte depletion was used in 6 patients with MDS from November 1999 to June 2007. 4 cases out of them received allo-PBSCT from HLA matched sibling donors with conditioning regimen of cyclophosphamide (CTX) and Bu. Graft versus host disease (GVHD) was prevented by the administration of immunosuppressive drugs of cyclosporine A (CsA) and short-course MTX. 2 patients received haploidentical allogeneic bone marrow transplantation (hi-alloBMT) after preconditioning with cytosine arabinoside (Ara-C), CTX and total body irradiation (TBI) with a linear accelerator. GVHD was prevented by the administration of immunosuppressive drugs including CSA, short-course MTX, MMF, anti-CD25 monoclonal antibody and ATG. The results showed that all of the patients were engrafted successfully. The median time of granulocyte recovery exceeding 0.5 x 10(9)/L and platelets exceeding 20 x 10(9)/L were days 15 and 20.3 respectively, and 100% donor hematological cells were detected by cytogenetic analysis. All patients did not experience serious acute graft-versus-host disease (aGVHD). During 18 - 108 months of following-up, 2 cases died of pulmonary complication and of relapse; the other 4 cases survive in a disease-free situation. In conclusion, allo-HSCT was an effective approach for the treatment of MDS.