OBJECT The purpose of this study was to clarify factors related to eating breakfast among elementary school children. METHOD The subjects were 196 fifth-grade pupils from two elementary schools in Osaka Prefecture. The main survey items were as follows: Number of eating breakfast days in the last week, appetite for breakfast, sleeping habits, knowledge on food, attitude related to eating breakfast, self-esteem, social skills, and eating behavior of family members. The Rosenberg Scale was used to measure global self-esteem and the Pope Scale for estimation of family-related self-esteem. Social skills were assessed using the scale developed by Shimada et al., which consists of subscales for pro-social skills, withdrawal behavior, and aggressive behavior. RESULTS The main results were as follows: (1) The percentages of children who ate breakfast everyday in the last week were 78.3% for boys and 70.2% for girls, who no significant difference between the sexes. (2) The children who ate breakfast everyday in the last week (everyday-eating group) had more appetite for breakfast and went to bed earlier than the children who one or more days without eating (lack-of-eating group). (3) Compared with the lack-of-eating group, the everyday-eating group showed higher scores in family-related self-esteem and pro-social skills, and lower scores for aggressive behavior. (4) Regarding knowledge on food except influence of sugar for health, there were no differences between the everyday-eating and lack-of-eating groups. However, the former included more children who thought that eating every breakfast was very important, compared with the latter. (5) Children who expressed the following answers were more abundant in the everyday-eating group than in the lack-of-eating group: (1) Family members prepare breakfast every day; (2) They ate breakfast with family members everyday in the last week; (3) They often talk with family members during meals and snacks. CONCLUSIONS From the above results, the following are suggested in relation to the development of eating breakfast for elementary school children: (1) Only providing knowledge on nutrition is insufficient; (2) Development of a positive attitude toward the significance of breakfast is necessary; (3) Development of a daily living rhythm, including sleeping behavior, is important; (4) Encouraging the development of family-related self-esteem and the social skills is important. Therefore, especially in the elementary school stage, not only conducting eating behavior education at school, but also intervention to affect family members' behavior and attitudes has an important role.