Osteoporosis will be one of the most important public health problem. But, until now there are a few available epidemiologic data of low bone density in postmenopausal women. This study was identify of leisure time physical activities on low bone mass. The subjects were 234 women and selected among the women who visited menopause clinic in one general hospital in Iksan. Data collection was conducted from September 4 to 8, 2006. Diagnosing low bone mass is to measure bone mineral density by using quantitative ultrasound (QUS) at the heel bone (calcaneus). Data were collected by means of a structured questionnaire. The study revealed that factors associated with low bone mass were age of ≥60 years, long duration after menopause (≥10 years), and physical activities (sports index, Leisure time activity index, total activity index). On the other hand, gynecological factors (menarche age, menopause age, duration of breast feeding, parity), body mass index, factors of life style and familial history were not associated with increased prevalence of low bone mass. Bone mineral density were positively correlated to sports index, leisure time activity index, and total activity index. The sports index, leisure time activity index, and total activity index were positively correlated with each others, but not for the work index. In multiple regression analyses suggested that an increase of age and decrease of leisure time physical activity associated with a highly risk of low bone mass. Results suggest that leisure time physical activity was found to be a practical instrument for predictor of low bone mass, and it should be considered intervention strategies for control osteoporosis, especially in postmenopausal women.