Objectives: The purpose of the study was to examine dietary life characteristics such as knowledge, self-efficacy and dietary behavior of preschoolers in Namyangju, Kyunggi-province, Korea. Methods: The survey questionnaire was developed based on literature review. Preschoolers aged 4-5 years (n=208) responded to the questionnaire to measure knowledge, self-efficacy, food preference, and dietary behavior. After excluding incomplete responses, the data of 197 subjects were used for analysis. Results: Mean score of dietary life knowledge was 8.0 out of 12, showing a low level of knowledge. Two out of 12 knowledge items were significantly different by gender. Percentage of correct answer on items of 'foods to make bones strong' and 'kinds of fast foods' was higher in girls than in boys (p<0.05). Total score of self-efficacy regarding dietary life was 40.1 (possible score: 12~48), on average. Compared to girls, boys had more confidence in 'not over-eating', and 'eating balanced meals with meat, fish and vegetables' (p<0.05). Boys scored higher on total score of food preference than girls (p<0.01). The preference for fruits was quite high. Among food items, boys scored higher on the preference for rice (p<0.01), fish (p<0.01), pork (p<0.05), beef (p<0.05), milk (p<0.01), and ice cream (p<0.05) than girls. Boys also liked fast foods more than girls did, showing preference for chicken (p<0.01) and soda (p<0.05). Compared to girls, boys showed more desirable behavior in 'eating breakfast everyday' (p<0.01). Dietary behavior was significantly correlated with self-efficacy (r=0.52, p<0.01), food preference (r=0.35, p<0.01), and knowledge (r=0.25, p<0.01) of subjects. Conclusions: In this study, we observed differences in food preference by gender. Dietary behavior of preschoolers was correlated with several factors, including dietary life related knowledge, self-efficacy and food preference. Thus, it is needed to develop nutrition education programs focusing on increasing dietary life related knowledge and self-efficacy, and consider the differences in food preference of preschoolers by gender.