To analyze the association between water sanitation and living conditions and dental caries in Brazilian schoolchildren. Material and Methods: A list containing names of children enrolled in 18 urban public schools was obtained. Then, data registered by community health agents from the family health strategy were consulted, aiming to obtain information about socio-environmental variables such as house type, number of rooms in the house, water supply, water treatment, waste, feces and urine disposal. For sample calculation, 95% confidence level, 80% test power and 5% error rate were used A total of 199 5-yearold and 137 12-year-old schoolchildren participated in the research. For examinations, World Health Organization recommendations for epidemiological surveys of dental caries were followed. Results: For 5year-old children, dental caries prevalence was related to municipality of origin, water supply system and sewage system. For 12-year-old children, untreated water and waste collection were related to higher dental caries rates. Conclusion: Dental caries was associated to house type and water sanitation.