Thirteen total knee replacements of the semiconstrained type were performed in ten patients with classic hemophilia (factor-VIII deficiency) and followed for two to six and one-half years. The average age at operation was twenty-seven years. Preoperatively, all patients complained of severe pain and were markedly disabled: five required wheelchairs and five needed crutches to walk. All patients had declared themselves willing to accept arthrodesis as the only surgical alternative. The results of the total knee arthroplasties, as determined by a standard knee-scoring system, were four knees rated as excellent or good and eight rated as fair. The thirteenth knee required an arthrodesis after a deep infection and was rated as a failure. Pain and function were markedly improved, and no patient required a wheelchair postoperatively. Although the postoperative knee motion was only slightly improved, it was in a range that meant a more functional knee. Postoperative complications included intra-articular or intramuscular bleeding in three patients and one posterior tibial and three peroneal-nerve palsies, one of which still was not completely resolved at the time of writing. Total knee arthroplasty in hemophilia appears to be a satisfactory procedure for reconstruction of the severely damaged knee when arthrodesis is the only other acceptable alternative.