OBJECTIVE To determine the bone mineral density curve in Turkish postmenopausal women and to evaluate the efficacy of estrogen replacement therapy in the prevention of bone loss. METHODS Spinal bone mineral density was measured using dual photon absorptiometry in 118 postmenopausal women, prospectively. Parity, previous and current use of estrogen preparations were correlated with BMD using Student's t-test and the chi 2-test. RESULTS With a mean BMD value of 0.967 +/- 0.013 g/cm2, 62.5% of our postmenopausal study population had a mean BMD value of < 1.0 g/cm2 and 33.7% were already osteoporotic (< 0.9 g/cm2). Bone loss was faster and more intense in the surgically menopausal than in the naturally menopausal group (P < 0.05). Parity after the fourth delivery dropped the mean BMD value (P < 0.05). Previous and current use of estrogen treatment seemed to decrease bone mineral loss in the postmenopausal years. CONCLUSIONS Our data stress the need for locally obtained normal BMD values in every country in the world. High parity, surgical menopause and duration of 5 or more years of natural menopause are risk factors for bone loss. Estrogen replacement diminishes the annual bone loss.