Background : Splenectomy is often performed for the patients with refractory chronic immune thrombocytopenic purpura(ITP). Still, there are no generally accepted guidelines for the minimum level of platelet count and the average requirement of platelet transfusion so that the patients can safely undergo splenectomy. We evaluated the changes of platelet count and transfusion requirements around the splenectomy in patients with chronic ITP Methods : We reviewed the medical records of 25 patients with chronic ITP. We compared the platelet counts at admission, immediately pre-op and several post-op days. We also investigated the number of platelet concentrates transfused around splenectomy We determined the effect of splenectomy according to Difino's classification. Results : The median platelet counts of the patients was 18×109/L(7-238 ×109/L) on admission and recovered to 108×109/L(22-460× 109/L) on preoperation day by platelet transfusion and immunosuppressive treatment. The platelet counts were rapidly recovered after splenectomy from the day of operation. Only 3 patients needed platelet transfusion after splenectomy. Thirteen among twenty five patients(52%) underwent operation without platelet transfusion support. Most transfusions were done before the surgery and 80%(12/15) of the patients required transfusion of more than 10 units of random donor platelet concentrate. Twenty one patients(84%) showed the complete remission after splenectomy. Conclusion : Splenectomy can lead to rapid remission even in most cases of refractory chronic ITP. Many cases can undergo the operation only with treatment modalities other than transfusion such as immunosuppressive agents and/or immunoglobulin. The minimum level of platelet counts for splenectomy may be safe over 50× 109L and about 10 units of platelet concentrate may be enough for preparation of splenectomy.