Impact of pretransplant splenectomy in patients with beta-thalassemia major undergoing an allogeneic SCT has never been addressed. Twenty-seven class III patients (29 transplants) had a pretransplant splenectomy. The outcome of these 29 transplants was compared with 76 transplants in class III who did not have a splenectomy. Patients in the splenectomy group were older (11.7 +/- 5.0 vs. 8.5 +/- 3.5 yr; p = 0.003) and had a larger liver size (5.7 +/- 1.8 vs. 4.4 +/- 1.6 cm; p = 0.000). Splenectomized patients had a significantly faster time to ANC >500/mm(3) (15.4 +/- 5.9 vs. 17.5 +/- 4 days; p = 0.002) and platelet >20 000/mm(3) (22.5 +/- 6.7 vs. 32.5 +/- 13.6 days; p = 0.000). The splenectomized group had a significantly reduced requirement of blood transfusion in the first 100 days post-transplant (5.5 +/- 5.1 vs. 7.2 +/- 5.4 units; p = 0.017). There were significantly more deaths related to peri-transplant infections in the post-splenectomy group (24% vs. 5.3%; p = 0.0001). The graft rejections were comparable between the two groups (20.7% vs. 14.5%; p = 0.55). The incidence of acute and chronic GVHD, late infections, and deaths from RRT was not significantly different between the two groups. The five-yr EFS (31.0 +/- 8.6 vs. 60.8 +/- 5.98; p = 0.003) and OS (39.7 +/- 9.3 vs. 71.8 +/- 5.5; p = 0.002) was significantly worse in the splenectomized group. In conclusion, pretransplant splenectomy among patients with beta-thalassemia major was associated with faster engraftment, reduced transfusion support, a higher incidence of peri-transplant infection related deaths, and a reduced EFS and OS.