Injuries, osteomyelitis, tumors are responsible of large skull defects. Their management is difficult. Three post traumatic and post infectious defects were repaired with an osteoperiostic flap taken from the internal face of the femur. A large defect due to the removal of a metastatic tumor was repaired with an iliac osseous flap. The choice of the donor site depends on the defect size (the femur provides a flap of 13 cm x 8 cm, the iliac bone a flap of 17 x 17 cm). The three head injured patients had a range of six previous unsuccessful surgical attempts using polymerised material or bone grafts. The post operative course in the post traumatic patients was uneventful, the domestic result good, the periostic consolidation less than three months. The free flap seems a good method for the management of risky cases.