An 11-year-old hemophiliac with a high level of Factor VIII inhibitor (50 Bethesda units) developed a pseudotumor of the mandible. Treatment with Factor IX concentrates was unsuccessful. Since surgical management was contraindicated, the patient was given 600 rad to the mandibular lesion, which resulted in complete recovery. The authors stress that radiotherapy may be successful in pseudotumor when surgery is contraindicated.