This study was to investigate relationship between osteoporosis and various factors. We compared the result in 390 women with under -2.5 bone mineral density (BMD, T-scores) with those in 370 women with over -1.0 BMD. According to WHO criteria, women with -2.5 BMD are regarded as patient with osteoporosis, while with above -1.0 BMD are healthy. We obtained the BMD(T-scores) data of 9.704 adult women over 20 year old. The following are the results of this study: The mean age of interviewed women was 45.7 years and their menopausal age was 48.6 years. Means of height and weight were 157.3cm and 56.9Kg respectively. The BMD was the highest in 30-34 year-old women, an average ranges were in the 35-44 year old group. The BMD decreased after 45 year-old. The early sixties women began to experience thiness of the BMD and the mid-sixties showed symptoms of osteoporosis. The formular showing the relationship between age and BMD can be represented as $Y=9.71X^2-2.71X+0.06$ (p<0.001). The bone mineral density decreased significantly with increases of age(p<0.001) and decreases of weight(p<0.001) in multiple regression analysis using age, weight, menopause age, height, number of pregnancies, number of children, and age as independent variables.