RESUMEN
OBJECTIVE: To identify the prevalence of caries in affiliated children and teenagers at Instituto Mexicano del Seguro Social (IMSS). METHODS: The survey was carried out according to the World Health Organization indexes. The studied was carried out in 1545 boys and girls aged three, five, six, and twelve years and selected by stratified random sampling in seven places of Mexican Republic (Guanajuato, East and West Estado de México, Northwest 1, Northeast 2, Southwest 3, and Southeast 4 DF). RESULTS: The prevalence of caries was 66.9 %. Rates were higher in temporary dentition than in permanent teeth (p < 3.07). The mean of caries index per tooth in primary dentition in children of six years of age was 3.57 +/- 2.8. In the 12 years of age group the average per tooth was 1.97 +/- 1.4. The main component in both primary and permanent dentition was caries with 2.49 and 1.56 respectively. CONCLUSIONS: The results of this survey showed slight changes in prevalence and high levels of caries in children.