In this paper we report our clinical investigation of three cases with acquired hemophilia A treated in our department. These patients were all elderly males (79, 77, and 68 years old), and presented with subcutaneous bleeding, a prolonged activated partial thromboplastin time (APTT), and anemia. On the basis of these findings as well as decreased factor VIII activities (0.9~3.1%) and the presence of factor VIII inhibitors (57.1~173 BU/ml), we made a diagnosis of acquired hemophilia A. In cases 1 and 2, a recombinant activated factor VII was used to achieve hemostasis. The factor VIII inhibitor disappeared with prednisolone (PSL) alone in case 1 and a combination of PSL and cyclophosphamide in case 2. In case 3, treatment involving five courses of weekly rituximab (RTX) reduced the activity of factor III inhibitor to 3.5 BU/ml (and subsequently to zero). During this time, the patient achieved hemostasis without using a specific hemostatic agent, and was again referred to the previous hospital for the treatment of hepatocellular carcinoma. Although PSL is often chosen as a first-line therapy to suppress the production of factor VIII inhibitor, which may cause acquired hemophilia A, RTX may be another therapeutic option in some patients.