Massive facial defects involving the oral sphincter are challenging to the reconstructive surgeon. This study presents the authors' approach to simultaneous reconstruction of complex defects with an advancement flap from the remaining lip and free flaps. From January of 1997 to December of 2001, 22 patients were studied following ablative oral cancer surgery. Their ages ranged from 32 to 66 years. Nineteen patients had buccal cancer, two patients had tongue cancer, and one patient had lip cancer. In all cases, the disease was advanced squamous cell carcinoma. Nine patients underwent composite resection of tumor with segmental mandibulectomy, and seven patients underwent marginal mandibulectomy. Cheek defects ranged from 15 x 12 cm to 4 x 3 cm, and intraoral defects ranged from 14 x 8 cm to 5 x 4 cm in size. One third of the lower lip was excised in nine patients, both the upper and lower lips were excised in 10 patients, and only commissure defects were excised in three patients. An advancement flap from the remaining upper lip was used for reconstruction of the oral commissure and oral sphincter. Then, the composite through-and-through defect of the cheek was reconstructed with radial forearm flaps in 13 patients, fibula osteocutaneous flaps in five patients, double flaps in three patients, and an anterolateral thigh flap in one patient. The free flap survival rate was 96 percent, and only one flap failed. With regard to complications, there were two patients with cheek hematoma, six patients with orocutaneous fistula or neck infection, and one patient with osteomyelitis of the mandible. All but one patient had adequate oral competence. All patients had an adequate oral stoma and could eat a regular or soft diet; two patients could eat only a liquid diet. For moderate lip defects, immediate reconstruction of complex defects took place using an advancement flap from the remaining lip to obtain a normal and functional oral sphincter; the free flap can be used to reconstruct through-and-through defects. This simple procedure can provide patients with a useful oral stoma and acceptable cosmesis.