RESUMEN
Background: Undernutrition and obesity coexist among Mexican children due to poverty, sedentariness and inadequate food intake. Aim: To assess the nutritional status of school age children in a Mexican city located in the frontier with United States. Material and Methods: Cross sectional assessment of children from 28 basic schools in 2005, 2008 and 2013. Using a cluster sampling methodology, 5 children per course were selected in each school, reaching a final sample 840 children aged 7 to 12 years old. Body mass index z scores were calculated. Results: The pre valence of overweight and obesity among these children was 49, 54 and 45% in the assessments performed in 2005, 2008 and 2013 respectively. Conclusions: There is a trend towards a decrease in the frequency of obesity in these children from 2005 to 2013.