PURPOSE: To determine the necessity of site-specific bone mineral density(BMD) measurement and the difference between the BMD of the two femora using DXA in the evaluation of osteoporosis. MATERIALS & METHODS: Total BMD and regional BMD(Lumbar spine, femoral neck, Ward's area, intertrochanter area) were measured on seventy-eight healthy persons without previons diseases, and the statistical significance analyzed. RESULTS: Total BMD did not reliably reflect the site-specific BMD. There was a high correlation between BMD in opposing femora. Correlation coefficients between the femoral neck, Ward's area, trochanter area were 0. 939, 0.874 and 0.916 respectively. CONCLUSION: We conclude that a measuremnt of site-specific BMD is necessory because the total BMD can not reliably predict the regional BMD. The measurement of BMD in one femur can predict the BMD of the contralateral femur. If there is no history of femoral neck disease, unilateral BMD measurement is recommended for femoral evaluation.