Rotational malalignment after IM nail of femur is a common problem and if the deformity is great, may cause pain, limitation of motion, even require corrective osteotolny later. The rotational malalignment of femur is not easy to find out during operation because prominant landmarks is lack. We experienced 25 years old male patient with 45 of internal malalignment of femur after IM nail at other hospital. The patient was treated by corrective osteotomy at the fracture site and exchange nailing, but we confronted the obstacle that was remained rotatonal unstability after slotted nailing, and we have to use additional plate fixation. This problem can be prevented by using rigid unslotted nail.