The factors that determine whether a proximal femoral fracture is neck or trochanteric area are a matter of controversy. So we studied the BMD(bone mineral density) and the morphology of the contralateral femur in subcapital fracture and intertrochanteric fracture(Boyd - Griffin Type I,II). The bone density of femoral neck, Ward's triangle and trochanteric region was measured by dual energy X-ray absortiometry(DEXA) in 41 patients with femoral neck fracture value and fracture type in same patients, we calculate the femoral neck length from the plain X-ray film. The results were as follows. 1. The ratio of BMD in the neck and trochanter area was higher in the trochanter fracture group. 2. The level of BMD of the trochanter fracture group was lower than the neck fracture group in all opints of measurement. 3. In the measurement of femoral neck length at plain X-ray film, the neck length of trochanter fracture group was longer than the neck fracture group. It may be that difference in BMD and femoral neck length is related to the site at which a proximal femoral fracture occurs.