Background Overweight and obesity arise from a complex range of genetic, environmental, behavioural, educational, and socioeconomic factors. Poor eating habits and poor physical activity increase the probability that children will become obese adolescents. The sedentary lifestyle, encouraged by the rapid evolution of technology, has been accentuated in recent years. Strategies to accelerate obesity prevention include modifying the child's environment for healthy eating and physical activity. For this, it is essential to analyze the characteristics and life habits of children population. This study tries to know the sedentary practices and some life habits related to health among children from the school population of Uruguaiana (RS, Brazil), identifying the sociodemographic factors that can influence it.Methods The sample was composed of 470 school boys and girls, aged between 9 and 10 years. In order to obtain the sample, a random plampling was performed by clusters of the 24 urban public schools of the city. Sociodemographic variables and sedentary habits were measured.Results As regards the variables linked to habits, 24% of the boys and girls answered they had not had breakfast the day they completed the questionnaire. 51.8% stated they did not have breakfast any given day of the week. Regarding to sedentary habits, 25.3% of children watched TV or played video games 5 or more hours a day and 9% rarely played sports with their parents or caregivers. Statistical significance was recorded between “number of hours watching TV and playing video games” and “playing sports with parents or caregivers” (p < 0.05).Conclusions Association between the times spent watching TV or playing video games and the practice of physical exercise in the family, proves once again the importance of the family in education for the health of children. The school provides direct Access to schoolchildren and their parents to launch numerous health education programs.