Posterior spinal fusion for scoliosis was planned in a 14-year-old male patient with hemophilia B. Preoperative examination showed factor IX activity of 8.4% with no inhibitor development. A perioperative dosage schedule was prepared after examining the pharmacokinetics of recombinant coagulation factor IX in order to maintain levels of perioperative factor IX activity at < or = 80% for the first 6 days (days 0-6), and > or = 40% for days 7-14 postoperatively. The dose of recombinant coagulation factor IX was adjusted to maintain factor IX activity above 80%, while measuring coagulation activity every hour during the surgery. The patient showed a favorable course without hemorrhagic tendency. We could safely manage anesthesia without requiring allogeneic blood transfusion.