The purpose of this study was to estimate the prevalence and to identify risk factors of overweight among preschool children in Korea. The study subjects were 750 children, aged 2-6, attending child care centers in Korea. A measurement of the height and weight of the children, as well as collection of wide range of variables including general characteristics, and potential factors related with dietary habit for children and their parents, were conducted. Overweight was defined based on more than 110% of ideal body weight. A logistic regression analysis was adopted to identify the factors associated with overweight. Subjects were classified into three categories according to the obesity index : underweight(PIBW<90%, n=34), normal(90%< or =PIBW<110%, n=577), and overweight(PIBW> or =110%, n=139). The overall prevalence of overweight and underweight of the subjects were 21.3% and 4.0% of the boys and 15.5% and 5.1% of the girls respectively. Parent's obesity was associated with a higher risk of overweight on girls. Subjects o the third quartile(girls) and fourth quartile(boys) of income level had a substantially higher risk of overweight than did those in the first quartile. Fast eating, overeating, and food prejudice were also associated with an increased risk of overweight. The results of a logistic regression analysis showed that the eating habits and food preferences of the children were the most influencial factors on overweight. These finding may imply the importance of early stage nutrition education on rational dietary habit to prevent prevailing obesity of preschool in Korea.