AbstractSplenectomy for massive splenomegaly in thrombocytopenic patients refractory to platelet transfusions carries increased surgical risks. Blocking of the splenic artery may reduce the size of the organ, prolong the survival of transfused platelets, and reduce the surgical complications. We describe four cases of extreme splenomegaly and thrombocytopenia where successful splenectomy was carried out after angiographic embolization of the splenic artery in children with ju venile chronic myelogenous leukemia. Significant improvement was observed in platelet counts and in the survival of platelets after transfusions in three of the patients. There was a concomitant decrease in transfusion requirements. Isoimmunization prevented prolonged platelet survival in the fourth case. We recommend earlier splenectomy in these patients to reduce transfusion requirements and delay the onset of poor platelet survival after transfusions.