The fibula was investigated as a donor site for free-flap mandible reconstruction. It has the advantages of consistent shape, ample length, distant location to allow a two-team approach, and low donor-site morbidity. It can be raised with a skin island for composite-tissue reconstruction. Twelve segmental mandibular defects (average 13.5 cm) were reconstructed following resection for tumor, most commonly epidermoid carcinoma. Five defects consisted of bone alone, and four others had only a small amount of associated intraoral soft-tissue loss. Eleven patients underwent primary reconstructions. At least two osteotomies were performed on each graft, and miniplates were used for fixation in 11 patients. Six patients received postoperative radiation, and two patients received postoperative chemotherapy. The flaps survived in all patients. All osteotomies healed primarily. The septocutaneous blood supply was generally not adequate to support a skin island for intraoral soft-tissue replacement. The aesthetic result of the reconstruction was excellent in most patients, particularly in "bone only" defects. There was no long-term donor-site morbidity.