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Background: The aim of this study was to investigate the effect of BMI and reproductive histories (age, age at menarche, the number of parities, reproductive years and years since menopause, and serum levels of estradiol, testosterone and SHBG) on bone densitometry of spine and femur in healthy postmenopausal women. Materials and Methods: In a descriptive cross-sectional study, 190 healthy postmenopausal women, aged 40-64, who did not have a history of co-existing diseases, diseases affecting the quality of life, bone diseases, and using drugs affecting the bone metabolism, were randomly selected. Bone densitometry, T score, Z score, and bone marrow density (BMD) were determined by dual energy X-ray absorptiometry (DXA) at lumbar spine and femur. Correlation co-efficients were, then, measured for the relationship between bone density and the intended factors. Results: BMI presented significant positive relationships with T score and BMD of spine and BMD, T score, and Z score of femur, whereas age, the number of years since menopause, and the serum level of testosterone had negative relationships with T score and BMD of spine. The serum level of testosterone showed a negative relationship with Z score reduction in spine. The number of years since menopause had a positive relationship with reductions in Z score and BMD of femur. In addition, significant positive relationships were observed between the number of reproductive years and T score and BMD of spine. Conclusion: Bone loss in postmenopausal women is intensified with increases in age, the number of years since menopause, and the serum level of testosterone, whereas BMI has a bone-protective effect.