Purpose: To evaluate caries experience and fluorosis prevalence in 12-year-old schoolchildren in Piracicaba, Brazil in 2007 and to verify the relationship of these changes with socioeconomic and behavioural variables. Materials and Methods: The sample consisted of 724 schoolchildren from public and private schools. A calibrated dentist performed the examination under natural light using CPI probes and mirrors. The mean number of decayed, missing and filled permanent teeth (DMFT) and the SiC (Significant Caries Index) were determined for dental caries and the Thylstrup and Fejerskov index (T-F) for fluorosis. Socioeconomic and behavioural variables were collected by means of a questionnaire. Multiple logistic regression analyses were performed to verify the relationship of caries and fluorosis with socioeconomic and behavioural variables. Results: The DMFT and SiC indices were 0.85 (±1.54) and 2.52 (±1.72). Fluorosis prevalence was 29.42%. The regression models showed that children whose families earned up to four minimum wages were 2.58 times more prone to having caries than those whose families earned over four minimum wages. Furthermore, children who visited the dentist were 4.27 times more likely to have DMFT > 0. However, for fluorosis, the regression model was not significant. Conclusions: The 12-year-old schoolchildren in Piracicaba presented very low caries prevalence. Significant associations were observed between the presence of caries, monthly family income and visiting the dentist. Considering dental fluorosis, the majority of the sample presented no clinical signs of fluorosis. Schlagwörter: dental caries, epidemiology, fluorosis prevalence