The purpose of this study was to survey the changes in dental caries prevalence in 3-, 4-, and 5-year-old nursery school children in Shinshinotsu for 3 years from 1986 to 1988. The results obtained were as follows: 1) The caries prevalence in 5-year-old Shinshinotsu children decreased from 1986, and was 87.5% in 1988, lower than the national survey in 1987. On the other hand, the number of df teeth per person and the incidence of type C caries increased in 5-year-old Shinshinotsu children. 2) The caries prevalence rate in 3-year-old Shinshinotsu children was 89.5% in 1988, rather higher than the national survey in 1987.