Recent advances in reconstructive surgery for head and neck cancer have improved the cure rate of advanced carcinoma, and the function of the organ. However, it still remains difficult to repair the mandible and oral floor. We devised a combined flap of myocutaneous latissimus dorsi and iliac bone, and applied it to two patients with advanced carcinoma of the oral cavity that invaded to the mandible (T4N3M0). Each patient received preoperative irradiation, totalling 30 Gy and 40 Gy. Two weeks before the extensive resection, a sufficient bony mass for the presumed mandibular defect was taken from the iliac crest and transplanted beneath the latissimus dorsi muscle. Defects of the mandible and oral floor were reconstructed using this combined flap immediately after the resection. The patients began to eat 2 weeks after surgery.