An unstable intertrochanteric fracture lacks continuity of the bone cortex on the opposing surfaces of the proximal and distal fragments. This cortical deficit is due to either comminuti- On on the medial aspect of the neck(calcar-region) or a large and separate posterior trochan-teric fragment. Treatment of unstable intertochanteric fracture have taken method to restore bony contact medially and posteriorly by anatomical reduction or displacement osteotomy. The authors analyzed the 60 unstable intertrochanteric fractures treated by anatomic reduction and internal fixation with a compression hip screw from January 1990 to December 1995. We made a comparative analysis of the postero-medial fixation with additional screw(Group I) and no fixation group(Group II). We tried to find the difference of operation time, blood loss, union time, weight bearing time, neck-shaft angle, sliding length of lag screw and complication rate in two groups. The results were obtained as follows: 1. The mean union time was 11.5 weeks in the Group I and 12.7 weeks in the Group II (p>0.05). 2. The mean weight bearing time was 6.1 weeks in the Group I and 8.3 weeks in the Group II (p<0.05). 3. The decrease of neck-shaft angle was 2.3 degree in the Group I and 5.2 degree in the Group II(p<0.05). 4. The sliding length of lag screw was 5.8mm in the group I and 11.2mm in the group II(p< 0.05). 5. The lower complication rate was obtained in the group I than in the Group II, but two groups showed no significance by statistical analysis. In conclusion, the postero-medial fixation with additional screw in the treatment of unstable intertrochanteric fracture of the femur are suggested that medial cortical stability can be gained and early weight-bearing can be allowed.