Purpose: This study was carried out to identify factors influencing osteoporosis in women at pre- and post-menopausal state. Methods: The subjects of this study were 52 pre-menopausal and 125 post-menopausal women who were assessed of bone density in one general hospital. The data were collected through review of clinical records and telephone interviews using a questionnaire. Results: In the pre-menopausal women, the factors influencing osteoporosis were regular exercise (protective factor) and age (risk factor). Regression analysis showed that the factors attributable to osteoporosis included educational level, weight, age and number of pregnancy, accounted for 41.89% of the total variance. In the post-menopausal women. the factors influencing osteoporosis were age (risk factor), low educational level (risk factor), low economical state (risk factor), high parity (risk factor), and intake of coffee (protective factor). Regression analysis also showed that factors attributable to their osteoporosis included age, educational level, number of delivery, intake of the coffee, regular exercise, number of pregnancy and duration of oral pill intake, accounted for 37.41 % of the total variance. Conclusion: In pre-menopausal women, regular exercise was one of the most powerful determinant of their bone mass. Therefore, it is necessary to participate in a regular exercise program to maintain peak bone mass density prior to the onset of menopause. In post-menopausal women, increased age was the most influencing factor of their bone mass. Therefore, it is essential to establish early diagnosis and management of osteoporosis after menopause.