Introduction. Caries of deciduous teeth in the population of Polish children is a significant health, social and organizational problem. Aim. The aim of the study was to evaluate the dentition of 3- and 4-year-old children in the Mazowieckie Province. Material and methods. The study comprised 393 kindergarten children aged 3 and 4 years in the Mazowieckie Province, 202 girls and 191 boys, including 159 children aged 3 years and 243 children aged 4 years. In all subjects the state of dentition was assessed. The prevalence of caries was calculated as the percentage of people affected by this disease, and the intensity of dental caries was determined using the dmft index. The results were compared with those that Polish researchers obtained in the 3 – and 4-year-olds after 2000. Results. In the studied group of 3- and 4-year-olds the prevalence of caries was 62.85%, among girls – 61.88% and among boys – 63.87%. For all subjects the average scores for dmft index were 3.22 and its components dt – 2.72 (decayed teeth), mt – 0.1 (missing teeth), ft – 0.4 (filled teeth). Conclusions. The prevalence and intensity of dental caries in 3- and 4-year-old children attending kindergartens in the Ma-zowieckie Province is high and close to the national average. It is advisable to increase the preventive and curative measures in this age group of children on dental caries.