We have done emergency vascularized composite graft by microsurgical technique for severe open fractures. It is essential for open injury to cover bones, joints, tendons etc. Vascularized composite graft for open fracture with tissue defect covers bone etc., prevents infection and promotes subsequent early functional recovery. Eighteen patients aged 3–55year old with an average age of 23.1y.o. were treated with this methos. Traffic injuries of leg and foot in children were the most common and others were open severe fracture with tissue defects. The composite graft employed were peroneal osteocutaneous flap, latissimus dolsi flap, parascapular flap and groin flap. The advantage of these flaps to cover the damaged structure primrily facilitatrs rapid tissue repair without infection and scar formation. In fact, except one reoperation due to a skin necrosis in parascapular flap, all grafted flaps successfully repaired the severe damaged bone and joint. Sufficient perfusion of antibiotics by these vascularized flap prevents infection in all cases. Primary emergency vascularized composite graft for severe open fracture with tissue defect is shown to be extremely useful method with rapid repair and functionnal recovery.