To compare the outcomes of patients with hematological malignancies who received ATG-Fresenius (ATG-F) 20 mg/kg versus those who received ATG-Genzyme (ATG-G) 10 mg/kg in an unrelated donor hematopoietic stem cell transplantation (HSCT) procedure, a total of 186 patients who underwent their first allogeneic HSCT with an unrelated donor were retrospectively analyzed. One hundred and seven patients received ATG-F, and seventy-nine patients received ATG-G. Multivariate analysis showed that the type of ATG preparation had no effect on neutrophil engraftment (P= 0.61), cumulative incidence of relapse (P= 0.092), nonrelapse mortality (P= 0.44), grade II-IV acute graft-versus-host disease (GVHD) (P= 0.47), chronic GVHD (P= 0.29), overall survival (P= 0.795), recurrence-free survival (P= 0.945) or GVHD-free relapse-free survival (P= 0.082). ATG-G was associated with a lower risk of extensive chronic GVHD and a higher risk of cytomegaloviremia (P= 0.01 and HR = 0.41,P< 0.001 and HR = 4.244, respectively). The results of this study suggest that the preparation of rabbit ATG used for unrelated HSCT should be selected based on the incidence of extensive chronic GVHD of each center, and the posttransplant management strategy should be adjusted according to the ATG preparation.