The treatment of extensive soft tissue injury is a chsllenge to Orthopedidic Surgeon especially in young children and at present reconstructive surgery with free flap is being employed under microscopy actively. The author present 27 cases of free flaps in young children below 6 years old, which were performed from March 1983 to December 1986. The results are as followes ; 1. The mean age was 4.9 years old. 2. The mechanism of injuries were all pedestrian injury. 3. We performed 27 cases of free flaps, among them 24 cases of flap were survived(88.9 %) with good functional and cosmetic result. 4. The vessels were larger in these young children than we expected. It is apparent that in a healthy child even though below 6 years old, the careful application of microsurgical principle is an excellent method for salvaging devascularized parts that are vital for function or appearance.