Introduction. Dental caries is still a social problem in many countries, including Poland. Through epidemiological studies conducted in index groups among children and adults, it is possible to monitor its progress and take appropriate action. The Podlaskie region is an area where the severity of dental caries in children has been the highest in the country for a few years, both in urban and rural settings. Objective. Evaluation and comparison of indicators of the progress of caries – Decayed Missing Filled Teeth (DMFT) – in 12-year-olds from the urban and rural areas of north-eastern Poland, measured between 2003–2010. Materials and method. In 2003 and 2010, respectively, 445 children were examined: in 2003 – 188: 101 boys, 87 girls; 98 from urban areas, 90 from rural areas, and in 2010 – 257 adolescents: 134 boys, 123 girls; 157 from urban areas and 70 from rural areas. The study protocol was strictly subordinated to the WHO study monitor guidelines. DMFT indices were evaluated in particular years. The distribution of their individual components was then compared and analyzed. The outcomes resulting from the place of residence and gender of the adolescents were taken into account. In the statistical analysis, Shapiro-Wilk test and Mann-Whitney U test were used. Results. In 2003, the mean value of DMFT was 4.76, and in 2010 it decreased to 3.36 (p<0.0001). In 2003, DMFT was 4.42 in the rural areas, and after 7 years it has risen to 4.77. There was a significant decrease in the value of the index (from 5.08 to 2.82, p<0.0001) in the urban areas. No significant differences based on gender were observed between these years. Conclusions. The values of caries intensity among 12-year-olds from the Podlaskie region, both in rural and urban areas, are still high. Among children from the rural areas, dental caries progression is more visible and has not improved during the years 2003–2010. These findings should lead to the development of programmes for the inhabitants of rural areas.