To determine the relationships between soybean food intake, dietary isoflavone intake, and osteoporosis incidence, questionnaire surveys, bone mineral density measurements, and dietary surveys by food record were performed with 19 postmenopausal women (57.6±7.3 yrs of age) in Daejeon city. The subjects were divided into two groups: an ‘osteoporosis group’ (OG, n=10) and a ‘normal group’ (NG, n=9). Mean age, height, and body weight were similar between the two groups but BMI was higher in OG than in NG. Mean age at menarche was not different between the two groups. However, mean number of childbirths was greater in OG than in NG and mean total period of lactation was shorter in OG. Mean exercise time per week was similar between the two groups, and mean time of sunlight exposure tended to be shorter in OG. Mean daily intake of calcium was lower in OG whereas sodium intake was higher in OG. Mean daily intakes of total soybean food (OG: 203.8±84.6 g/d, NG: 285.0±146.3 g/d) and total dietary isoflavone (OG: 29.1±14.3 mg/d, NG: 38.3±23.1 mg/ d) were not different between the two groups. However, greater intakes of soybean food and dietary isoflavone were associated with higher bone mineral density, respectively. The above results indicate that osteoporosis incidence tends to be influenced by BMI, maternal factors, dietary nutrient intakes, soybean food intakes, and dietary isoflavone intakes in postmenopausal women; although no significant differences in soybean food and dietary isoflavone intake were found between the two groups. This tendency implies that greater intakes of soybean food and dietary isoflavone lead to lower incidence of osteoporosis in postmenopausal women.