In spite of the numerous complications of transfusion therapy, there is no doubt that development of convenient clotting factor concentrates for home care has revolutionized the care of patients with hemophilia. With the obvious exception of HIV infections and chronic hepatitis, the majority of patients have few clinically significant adverse side effects in spite of years of replacement therapy. The development of improved viral attenuation processes may have eliminated the viral contamination of these products, but this is yet to be confirmed. The recent breakthrough in the development of highly purified, genetically engineered FVIII products will, it is hoped, eliminate all of the complications of therapy with the exception of inhibitor development. The development of recombinant FVIII replacement should ultimately lead to the availability of reasonably priced products in potentially unlimited supply. If this can be achieved, we may be able to look forward to prophylactic infusion therapy for patients with severe FVIII deficiency and eliminate the significant complications that continue to occur even with prompt treatment of hemorrhage and thrombosis.