The aim of this study was to investigate the awareness and attitudes for leftover foods and the relationship between gender/number of family members on the effect of leftover foods-free day in elementary school students. The reasons for school lunch leftover foods were ‘too much amount (38.3%)’ and ‘disliked menu (33.6%)’, and the preferred ways for reduction of leftover food was ‘to cook deliciously (34%)’. In the case of students who received nutrition education for reduction of leftover lunch, approximately 33.8% of subjects received nutrition education by administered by nutrition teachers during lunch time. The reason for reducing the amount of leftover foods was ‘not to waste the foods (35.5%)’. After a leftover food-free day, approximately 62.3% of subjects responded that they ate their whole meal, except for soup. The subjects wanted ‘twice per week for leftover food-free day’ and had positive attitudes for that program. Proportion of practicing reduction of leftover foods in families was 55.9% of subjects, and 40.5% of subjects preferred dietary education by nutrition teachers in the classroom. For effective reduction of leftover lunch in school, nutrition teachers should attract interest on the environment and foods through after-school activities.