Estrogen deficiency is an important contributing cause of osteoporosis, and the resulting disabilities associated with vertebral and hip fractures. Hormone replacement therapy(HRT) at the time of the menopause has been shown to be effective in preventing menopause-related loss of mineral. However, estrogen therapy is not commonly recommended for older postmenopausal women because esttogens do not increase bone mass and are therefore ineffective in the treatment of established osteoporosis. However, recent studies found significant increases in Bone Mineral Density(BMD) of the spine in response to estrogen in older women but not in BMD of the femur. In this study, changes in BMD of the femur(neck, Ward's triangle and trochanter) in response to 1 year of HRT were evaluated by dual energy X-ray absorptiometry(DEXA) in postmenopausal women. One hundred seven women, naturally menopaused, received HRT with estrogen alone or in combination with progesterone, The purpose of this study is to analyze the effect of HRT on BMD of the femur in postmenopausal women in relation with years since menopause and initial bone mass. The results wete as follows; 1. Percentile increases in BMD of the femur(neck, 3.2%/year; Wards triangle, 1.7%/year; trochanter, 5.6%/year) occurred in response to HRT. 2, There was no correlation between the effect of HRT on BMD of the femur and years since menopause. 3. The changes in BMD of the femur(neck, Wards triangle, trochanter) in response to HRT were significantly related to the initial bone mass(neck, r 0.32; Ward's triangle, r= 0.41; trochanter, r 0.40). These results suggest that HRT significantly increases bone mass of the proximal femur as well as the lumbar spine and the response to HRT on BMD of the femur was greater in those had lower bone mass. Therefore, HRT may be effective in preventing osteoporotic fractures of the femur in older postmenopausal, osteopenic women.