A large study amongst 6-7 years old children was conducted in one of the German Federal States to evaluate the success of presently existing prophylaxis programs and to determine groups at high risk for dental caries. - A total of 3880 children (1844 girls and 2036 boys) received a dental exam while in first grade in the year 2000. 37.8% (n = 1465) of the students lived in a larger city (approximately 200000 inhabitants), 62.2% (n = 2415) of the students came from rural areas. The proportion of foreign children, mainly from Serbia, Croatia and Turkey, amounted to a total of 19.1% (n = 741). All children were cared for as part of a group dental prophylaxis program in their respective schools and were examined under the protocol of the dmf-t/DMF-T index. 53.4% (n = 2073) of the students had a naturally healthy dentition, with the percentage of boys (55.5%, n = 1129) being higher than that of girls (51.2%, n = 944). The percentage of the caries-free dentitions in the rural population was 56.1% (n = 1163) whereas the percentage amongst the urban students was 43.9% (n = 910). The percentage of naturally healthy dentitions was 60.8% (n = 1909) amongst German children, and their foreign classmates had 21.9% (n = 162) caries-free dentitions. 37.6% (n = 1459) of all children had carious lesions; the foreign children had carious defects in 69.7% (n = 517) of the cases and the German students in 30.1% (n = 944). 8.8% of all first graders surveyed had fully treated healthy dentitions. - Although the goal of the WHO to obtain caries-free dentitions amongst 5-6 year olds in 50% of the cases has been met in the year 2000, this study showed clearly that oral health was significantly worse for the majority of foreign children compared to the German school children.