Introduction: The objective of the study was to determine the prevalence of dental cavities, periodontal disease and dental fluorosis, and to evaluate knowledge, attitudes and practices among schoolchildren between the ages of 6 and 13, enrolled at the Colegio Silveria Espinosa de Rendón Sede b, in Bogotá, Colombia in 2013. Methods: a crosscutting descriptive study; proportional stratified randomized sample of 205 children, of whom 190 were finally evaluated after their parents or guardians signed informed consent forms. The following factors were evaluated: Green and Vermillon Simplified Oral Hygiene Index (sohi), Klein cop-d Index, Gruebbel ceo-d Index, Deany Index and Russell Index. Thoughts, attitudes and practices were evaluated using a survey. The inter-operator error was 0.8. The information was analyzed using Version 13.8 statistical software. Results: Oral hygiene among the schoolchildren is fair to middling. The cop-d Index was 1.79, classified as a low-level for dental cavities. The ceo-d Index was 2.57. According to the Russell Periodontal Index, these children would be classified as having reversible periodontal disease. The community dental fluorosis Index was 1.04. The schoolchildren have adequate levels of knowledge, but in terms of practices, they frequently do not make periodic visits to the dentist. Conclusions: A large proportion of the schoolchildren are affected by fluorosis and periodontal disease. Activities must be carried out to modify their oral hygiene habits and inculcate appropriate brushing techniques.