Objective : This study investigates whether the working status of mothers results in an unbalanced diet (no acceptance of disliked foods) of their preschool children, and the relationship of the preschool children's unbalanced diet and its relevant factors.<br>Methods : This cross-sectional study was conducted using the responses of 1,145 mothers at 15 public kindergartens in a suburban city located in the Kanto region. A self-rating questionnaire examined mother's age and working, child's age and gender, the unbalanced diet of mother and their child, and eating education provided to child.<br>Results : The unbalanced diet of children were not associated with the working status of their mothers. Among non-working mothers, the causal factors of the unbalanced diet of their children were classified as the unbalanced diet of the mother, neglecting to instruct child not to waste food, not giving to child's meal child disagreeable foods or weak foods. Among working mothers, not engaging their child to help in the preparation of meals was the most prominent cause of children's diet unbalances.<br>Conclusion : It was suggested that although the working status of mothers has no direct effect on the unbalanced diet of their childrens, differences in the factors relating to the unbalanced diet of their childrens depend on whether the mother is employed or unemployed.