Twenty one cases of adult tibial shaft fractures were fixed with flexible intramedullary nails at the Department of Orthopedic Surgery, Kang Nam General Hospital. The results are summerized as follows; l. Average healing time was 17 weeks. No case of nonunion was experienced. 2. As the operation was perfomed by closed method under fluoroscopic control, reduction of operation time is a major advantage. 3. Fixation was usually strong enough to allow immediate weightbearing and mobilization of the adjacent joints without external immobilization. 4. Three cases of delayed union and 2 cases of rotational malunion were experienced, but shortening and angulation were not so severe as to affect overall functional results. 5. In conclusion, Ender nailing is considered to be a valuable method in treating tibial shaft fractures. Even in cases with multiple injuries and in selected open cases, Ender nailing can be a saft procedure.