This study was aimed at evaluating the stability of internal fixation for the femoral intertrochanteric fractures with and without adjunctive methylmethacrylate by the biomechanical study under the vertical compressive load. Two part intertrochanteric fractures were produced in twenty two embalmed adult femora without previous evidence of fracture, disease or deformity. Femora were fixed at 8501 Material Test System with an angle of 66 degrees of inclination from the horizontal and vertical compressive loads were applied over the femoral head. Twenty-two femora were divided into three groups. Preliminary experimental group (two specimens) was fixed only with methylmethacrylate. Experimental group I (thirteen specimens) was fixed with 135-degree angled compression hip screw, and experimental group II (thirteen specimens) was fixed by combination of 135-degree angled compression hip screw and adjunctive methylmethacrylate. Various biomechanical properties of fixation methods for the femoral intertrochanteric fractures were measured, such as maximal force, bending moment, ultimate stress, energy absorption capacity, stiffness coefficiency, strain. Strain was analyzed using the strain gauge affixed to the outer surface of the plates and medial calcar of the specimens to measure length changes of bones and metals by Poisson's effect. The results of the study could be summarized as follows. l. In the preliminary experimental group, the maximal force was 377±72.1kp (Mean±S.D.), the bending moment 200.8±12.7Nm, the ultimate stress 4333±754(X104N/m2), energy absorption capacity 1602±144 kp mm, and stifffness coefficiency 63.2±10.6kp/mm. 2. In the experimental group, the results of group I and group II were compared. 1) The maximal force of the group I and II were 50.6±119.7kp (Mean±S.D.) and 766±209.5kp respectively and the difference was statistically significant. 2) The bending moment of the group I and II were 297.2±69.9Nm and 526.9±152.3Nm respectively and the difference was statistically significant. 3) The ultimate stress of the group I and II were 5910±1431(X104N/m2) and 9587±2694 (X104N/m2) respectively and the difference was statistically significant. 4) The energy absorption capacity of the group I and II were 1863±515 kp mm and 3050±116 kp mm respectively and the difference was statistically significant. 5) The stiffness coefficiency of the group I and II were 95.9±40.1kp mm and 112.9±50.6 kp mm respectively and the difference was statistically insignificant. 6) The calcar compressive strain during 300kp loading of the group I and II were -498±272 (X10-6) and -1549±517 (X10-6) respectively and the difference was statistically significant. 7) The plate tensile strain during 300kp loading of the group I and II were 1077±322 (X10-6) and 141.2±55.69.9 (X10-6) respectively and the difference was statistically significant. 3. This biomechanical study could indicate that the use of adjunctive methylmetharcylate with compression hip screw may supplement the initial stability of fixation in patients with femoral intertrochanteric fracture and severe osteoporosis and could permit the early weight bearing as its advantage.