SUMMARYObjective: To determine the prevalenceof fluorosis in children from 5-9 yearsof age, who have lived since birth in thecorregimiento de Montebello (Cali), andstudying in the Institución Educativa SanPedro Apóstol.Materials and methods: Cross-sectionalstudy with a sample of 60 school children.It was divided into three phases: Phase I:Measurement of minerals from the waterfountain at school. Phase II: Data Collectionon: risk factors and oral hygiene,through a survey of 27 questions. PhaseIII: Clinical examination to identify thepresence of fluorosis using the TFI index.Results: The average concentration offluoride in water was 1.0202 ppm. Theprevalence of fluorosis was 78.4%.Conclusion: The study population has ahigh prevalence of dental fluorosis.Key words: Fluoride, dental fluorosis,epidemiology, oral health.