Acquired hemophilia is a rare disorder associated with serious bleeding in nonhemophilic patients. We had a 40-year-old woman who was diagnosed as acquired hemophilia with a factor VIII inhibitor level of 27.5 BU/mL. She was presented with gross hematuria and severe right shoulder pain, and was successfully treated with daily oral cyclophosphamide and prednisone for 2 weeks. After the remission, the doses of prednisone and cyclophosphamide were slowly decreased and she remained in complete remission without further bleeding episodes.