Hemophilia A is an X-linked disorder resulting from a deficiency in factor VIII. Hemophilia A is classified into severe, moderate, and mild forms. A 12-month old boy visited for uncontrolled bleeding on the upper labial frenum area. Spontaneous bleeding occurred about 13 days ago. We sutured the wound. However, the patient returned after 6 days with large hematoma formation. Consultation to the hematologist and laboratory examination were carried out. Activated PTT was elongated and factor VIII was only 6%. He was diagnosed as mild hemophilia A. Fresh frozen plasma (FFP) was provided and hemostasis was achieved. At 5-day check-up, no more bleeding was observed. For the management of prolonged bleeding in hemophilia A patient, not only local hemostatic measures, but factor VIII replacement therapy, antifibrinolytics, and Desmopressin are also available. Mild hemophilia A often occurs without either familial or medical history. It is often first detected by dental trauma