It is unknown whether the addition of antithymocyte globulin (ATG) to reduced-intensity conditioning with busulfan (BU) and fludarabine (FLU) is beneficial in HLA-identical sibling transplantation. Therefore, we analyzed retrospectively data on 83 patients, who received peripheral blood stem cells from HLA-identical siblings after conditioning with either 8 mg/kg BU and 150 mg/m2 FLU (n=45) or 8 mg/kg BU, 180 mg/m2 FLU and 40 mg/kg ATG (n=38). Graft-versus-host disease (GVHD) prophylaxis consisted of CSA alone (n=32) or a combination with either MTX or MMF (n=51). The median age was 52 years. Graft failure occurred in two patients after BU/FLU and in three after BU/FLU/ATG (P=0.66). After conditioning with BU/FLU, platelet recovery was significantly faster (P=0.017), and less platelet (P