This study was undertaken to investigate dietary status, food habits, and nutritional knowledge of university students majoring in judo (n=239) and to evaluate the effect of dietary behavior on their athletic activities. Mean daily dietary intakes (3,854.0 kcal) were similar to mean daily energy consumptions (3,975.5 kcal). Average daily intakes of most vitamins and minerals were higher than Korean Recommended Dietary Allowances except for the intake of vitamin A. Self-confidence on judo affected dietary behavior of the subjects: Subjects who had more self-confidence on judo showed more interest in good nutrition and concerned more about foods which could promote their athletic activities. Many side effects were manifested after sudden weight control for judo competition during school days. Therefore, it is suggested that good education on nutrition is necessary not only for athletic students, but also for coaches and trainers of the students. Ten weeks of education on nutrition significantly improved both food habits and nutritional knowledge of the subjects. Food habits were positively correlated with self-confidence on judo. Therefore, it is suggested that improvement of food habits through good education on nutrition would be helpful to improve athletic activities of the students.