Objective: to assess food consumption and physical activity patterns of school children from the Aysen Region in order to develop an obesity prevention program. Patients and methods: the group studied was a representative sample from the school children from playground to fourth grade (n = 340). Sociodemographic, as well as food and physical activity patterns were obtained from interviews conducted at each participant s house. Frequency and intake level of selected foods were studied and compared with Ministry of Health recommendations. An index of overall diet quality was developed based on Chilean food pyramid and food consumption guidelines. Results: average age was 7.7± 1.6 years. Vegetables, fruits, and dairy products were among foods with low frequency of consumption. On contrast, high consumption frequency of mayonnaise, lard, and soft drinks were observed. High-fat meats and lacteous products were commonly consumed. Adequacy by food groups showed low figures regarding vegetables, fruits and dairy products, and high values on fats (oils), sugar and meats, mainly in women. Median for quality index was 3 (p 25 = 2, p 75 = 4), over a maximum of 7, without significant differences neither by age, sex nor nutritional status. Median of physical activity was considered as low: 6 walked blocks/day (95% CI 4.5-6.0), sports and active games 4 hours/week (95% CI 4-4). Conclusion: the food and physical activity patterns of school children from Aysen are inadequate. It is necessary to elaborate plans to promote healthy life stiles as preventing measures for obesity