Based on findings from anatomical dissections of the skin of the peroneal artery, we used the osteocutaneous fibula flap for combined replacement of the mandible and floor of the mouth in 24 patients, form November 1993 to December 1995. There were 22 primary and 2 secondary reconstructions; the mean age of the patients (2 women and 22 men) was 64 years. The length of the fibula segments ranged between 5.5 and 18 cm, the size of the skin component between 3 x 5 and 6 x 15 cm. Corresponding to the results of our anatomical studies, the skin island was exclusively raised form the distal third of the lower leg, and the donor sites were generally covered with split thickness skin grafts. The average length of the dissected vascular pedicle was 11 cm, so that a vein graft was only required in one case. Flap raising and tumour resection were always carried out simultaneously. Fibula osteosynthesis was done with titanium miniplates; the insertion of endosseous implants followed secondarily. The success rate was 95.8% with one transplant loss and pseudarthrosis in one case. Despite the limited width of the fibula, the shape of the mandible was satisfactorily reconstructed in all patients, and the thin, pliable component enabled intraoral coverage with only negligible surplus volume. Chronic wound-healing disturbances at the donor site of the skin island occurred in two cases; impairment of walking ability was not detected. According to our experience, the use of the osteocutaneous fibula flap is a valuable method for the reconstruction of composite mandibular defects.