When femoral shaft fracture with severe communition and segmentation result from violent force, they are frequently associated with severe soft tissue damage. Treatment of this unstable fracture need the rigid fixation in order to prevent shorting and rotational loading. In terms of this advantages, interlocking nailing technique was widely used with open and closed methods. In the cases of fractures that having large fragments and wide displacement, closed technique has disadvantage of difficulties in anatomic reduction and its maintenance. Nineteen femoral shaft fractures had been treated by these techniques alternatively at our hospital between Feburary 1994 and Feburary 1997 and had been followed for more than 12 months. Among the 19 cases, closed techniques were 11 cases and open 8 cases. We evaluated the results of two treatment methods in terms of the bone union time, complications and functional results. Mean duration of the bone union time was 24.2 weeks in closed interlocking nailing, 24.5 weeks in open. There was no difference between the bone union time and the operation techniques(p-value>0.05). And complications were delayed union in two cases. In conclusion, in the cases of severe comminuted and segmental femoral shaft fractures especially with posteromedial fragment, open technique was more useful than closed technique, in terms of anatomic restoration and getting functional recovery afford to preinjury level of work.