Objective: To assess the nutritional status, food consumption and physical activity (PA) habits of Chilean school children, as a baseline for developing an educational intervention. Design: Cross-sectional study. Subjects: A total of 1701 children from 3rd to 7th grade in nine schools located in three geographical regions. Methods: We determined body mass index, food consumption (quantified FFQ which we categorised into five groups), PA in terms of TV viewing and frequency of after school PA. The data were analysed according to age, nutritional status and gender. A logistic regression analysis was performed using obesity as outcome. Results: Obesity was higher among boys; younger children presented higher prevalence in both genders. Daily intake of dairy products varied between 240 and 308 g, fruits/vegetables, between 197 and 271 g, energy-dense foods between 343 and 460 g. In all, 22.3 and 47% of the children watched over 3 h of TV during the week and weekend, respectively. Older children watched significantly more TV during the week, while on weekends all children increased this time significantly. Boys were more active than girls after school. The logistic regression analysis showed a significant association between obesity and low intake of dairy products. Conclusions: Prevalence of obesity among Chilean children is high. Although TV time, intake of energy dense foods and fruits/ vegetables appeared as risk factors for obesity, only dairy consumption was significantly associated with obesity. Sponsorship: FAO