Introduction. Studies mainly performed in adults have shown an association between the amount of sleep and obesity. Objective. To determine if there is an association between nocturnal sleep deprivation during the week and the weekend, eating habits, physical activity and nutritional status among Chilean schoolchildren. Population, Material and Methods. Crosssectional study. An anthropometric assessment was done among 6-11 year-old students; the Pittsburgh Sleep Quality Index (PSQI) was used among parents to measure their children´s quality of sleep; they were asked about eating habits and physical activity. Results. One thousand eight hundred and ten schoolchildren of both sexes, attending public schools in Santiago, were assessed. Out of these schoolchildren, 49.9% slept fewer hours per night than recommended. An association in the crude model (crude OR 1.82; CI 95%: 1.29-2.56), in model 2 adjusted for cola drinks (OR 1.83; CI 95%: 1.30-2.59) and in model 3 adjusted for dinner, cola drink and caffeine beverage consumption and nocturia (OR 1.85; CI 95%: 1.30-2.62) was observed. It was also noticed that exercising was a protective factor against overweight and obesity; however, periodic limb movement during sleep was a risk factor. Conclusions. This study showed an association between fewer hours of sleep and an increase in the risk of overweight/obesity.