This study is performed to investigate whether free transplanted iliac physis can grow in the resected epiphyseal plate and prevent growth arrest secondary to an injury of epiphyseal plate. Growth arrest, angulation and regeneration of epiphyseal plate after free physeal transplantation from iliac crest in the partial resection of epiphyseal plate on the lateral aspect of the distal femoral epiphysis were analysed in process of time and compared with those of the simple partial resection of epiphyseal plate of distal femur. Seventy-six skeletally immature, three month-old rabbits with an initial weight of about 1200 to 1400gm were used for this study. The following experimental groups were made after partial resection of epiphyseal plate on lateral aspect of distal femoral epiphysis(2×7×3mm). Group A: partial resection alone(19 rabbits); Group B: muscle piece interposition(19 rabbits); Group C: free autogenous iliac crest physeal transplantation (38 rabbits). The opposite side of the leg was used as a control. Animals were killed and examined at the following time-intervals(14, 21, 30, 60 and 90 days after operation). The following results were obtained. 1. In the group of partial resections alone, the bone-brige formation between the femoral epiphysis and metaphysis revealed as early as 14 days, and this bridging was found consistently in all anlmals, which led to the growth arrest and valgus deformity. 2. In the group of muscle piece interpositions, the interposition materials were found temporarily effective for the prevention of epiphysiometaphyseal bone-bridge formation, but the effect was not significant to regain bone growth. 3. Histological studies showed that the grafted physis united with the residual part of the original femoral physis at 14 days after transplantation, and regained its columnar arrangement. The physeal graft appeared to be viable and contribute endochondral bone formation in following section (60, 90 days). 4. In the grodp of free autogenous iliaccrest physeal transplantations, the transplanted physis prevented or minimized the formation of a bone brige, growth arrest, and valgus deformity in most animals. Although not all of the physeal transplants were successful, physeal grafts would be most suceessful method regaining bone growth after focal injury of epiphyseal plate.