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. METHOD: 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 chi2-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/cm 2) . 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. CONCLUSION: 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.