We describe a reliable composite osteomyocutaneous flap used for mandibular reconstruction in 14 patients. The flap is composed of the pectoralis major muscle and the attached fifth or sixth rib, with the overlying skin. This flap is tunneled superiorly under the neck skin. The muscle protects the great vessels. The skin lines the oral cavity or fills an external skin defect, and the rib replaces lost mandible. The rib seems to be adequately vascularized to survive, and does not resorb. Boney union is painless and clinically firm. One flap in the series was lost, and the rib was removed in 3 others. There was 1 persistent fistula.