Approximately 15 percent of patients with hemophilia A will develop inhibitors (antibodies) to Factor VIII after replacement infusion. Since Factor VIII replacement therapy is the mainstay of treatment in the hemophiliac, destruction of infused Factor VIII by inhibitors presents significant problems in the treatment of these patients. Different methods of treatment are discussed, including infusion of high doses of Factor VIII and infusion of prothrombin-complex concentrate. Two inhibitor patients who presented for dental treatment are examined. One patient had very low inhibitor titers, and the other had very high inhibitor titers. These patients show that dental treatment must be individualized according to severity of the disease process.