To assess dental decay, gum diseases and fluorosis prevalence and evaluate treatment needs of public preschool children. A cross-sectional epidemiological survey on oral health was conducted in 2,805 public preschool children aged 5 and 6 years in Piracicaba, Brazil. Children were examined by a team of ten trained dentists. It was applied a consensus technique and intra and inter agreement among examiners was assessed using the percentage of agreement. Of the total, 44.3% children were free of dental decay at the age of 5 and 38.5% at the age of 6. The deciduous decay teeth index (dmf-t) was 2.64 at the age of 5 and 3.07 at the age of 6, and 31.9% and 37.9%, respectively, presented dmf-t greater than 3. The largest percent of treatment need (45.3%) was surface restoration. Regarding gum health, 68.6% and 72.6% of children aged 5 and 6 years presented gum bleeding. The prevalence of fluorosis was 2.6% at the age of 5 and 6.1% at the age of 6. It is necessary to develop appropriate actions and strategies for higher risk groups.37247-53