Objectives1) Determine the prevalence and severity of caries in children from two farms («roças») in S. Tomé; 2) Verify differences for caries prevalence and gravity in the farms; 3) Describe, in the same population, some oral health related behaviors. Material and MethodsCross-sectional study, with application of a questionnaire and oral observation by a calibrated examiner, using WHO criteria. The sample included 113 volunteer children. The analyse included descriptive and inferential statistic with Mann-Whitney and χ2 tests (α=0,05). ResultsThe mean age was 8,1±2,41 years. Carie's prevalence was 58,9% in primary dentition and 38,8% in permanent dentition. The mean dmft/DMFT was 1,8(±2,25) for deciduous teeth and 0,9±1,55 for permanent dentition. There were differences between the two farms considering caries prevalence in the permanent dentition and severity in both dentitions. Almost all decayed teeth remain untreated. Although most children (62,5%) consider teeth important, 98,2% did not know what a carie was. The majority (58,4%) of participants had toothache experience, but only 7,3% reported dental treatment. The consumption of cariogenic food was mentioned as frequent, particularly the sugar cane. Only 18,6% of the participants reported a to brush teeth two or more times per day. ConclusionsThe observed children have poor oral health related knowledge and presence of risk factors for caries. Nonetheless the studied population had a low to moderate prevalence and severity of caries, with the vast majority of decayed teeth remaining untreated. Canavial farm demonstrated worst oral health indicators.