The management of large defects after head injury, osteomyelitis or both is usually solved by the use of bone grafts, polymerised material or metallic prosthesis. The post-operative course is often frustrating when those materials are close to the frontal sinus leading to the removal of this material. For these reasons, we decided to use free periostic flaps for the management of these skull defects. The flap comes from the internal part of the femur creating no other defect in the body. Three patients with post infectious and post traumatic skull defects have been operated. The postoperative course was uneventful, the cosmetic result good and the protection of the cranial content effective after three months. Of these three patients one had eleven previous attempts of repair for his defect. This method seems to be a good one for those risky cases, and somewhat better than the use of great omentum transfer sometimes associated with bone grafts.