In order to identify practices and attitudes on food and physical activity in obese children of a low socioeconomic level, a survey was applied to 88 school children (41 boys, 47 girls) aged 8 to 11 years of age from Santiago. Sixty eight children and their mothers participated in 16 focus groups (4 groups of boys, 4 of girls and 8 of mothers), where motivations, barriers, self-esteem and self-efficacy related to food and physical activity were studied. Survey results were analyzed with the non parametric Mann-Whitney Test. A content analysis was made with the information collected in the focus groups; it is presented in terms of children's expressions. A low dietary intake of dairy products, fruits and vegetables (g/d), and a high intake of energy dense foods and beverages were found. More than 55% of children never engaged in after school physical activity. Children showed limited motivations and multiple barriers related with healthy food and physical activity habits, as well as low self-esteem and self-efficacy. Their mothers showed lack of motivation and low self-efficacy in providing support to their obese children. These results will be used as baseline information for educational interventions for preventing child overweight through motivation and self-care