This study was carried out to identify bone mineral density(BMD), body composition, lifestyle and dietary habits of young women by physical measurement and questionnaires. The study subjects, 190 young women living in Seoul, were divided into three age groups: $20{sim}24$ years(93), $25{sim}29$ years(44) and $30{sim}39$ years(53). There was no significant difference in mean body muscle mass, protein, mineral, body fat and BMI among the three age groups. The rate of low weight(18%) in 20 years group was higher that of the 30 years(11.3%). The mean BMD and T-score were $0.44g/cm^2$ and -0.66. BMD and T-score of the forearm bone were significantly higher in the $30{sim}39$ years group. But BMD and T-score of calcanues were not significantly different among the three age groups. The rate of normal, osteopenia and osteoporosis subjects by BMD were 60.5%, 38.4%, 1.1%, respectively. The rate of osteopenia in $20{sim}24$ years group was significantly higher than the other age groups. The rate of meal irregularity was significantly higher in $20{sim}24$ years group. The rate of women who walk and are exposed to sunlight more than 1hr per day were significantly higher in $20{sim}24$ years group than the others. However, the score of food behaviors is significantly higher(bad) in $20{sim}24$ years group than the others. The relationship between BMD and frequency of food intake showed significant differences in beans, broom, seaweed and rice wine. In conclusion, the risk rate of BMD was very high, 40% of the subjects, and the risk rate of BMD was higher in 20 years group than 30 years group, and the rate of low weight in 20 years group was higher than in 30 years group. The food habits and behaviors were not healthy enough. Therefore, nutrition education is needed for bone health.