In 1973 an epidemiological study was performed in the community of Jönköping, Sweden. The study covered 1000 individuals, evenly distributed in the age groups 3, 5, 10, 15, 20, 30, 40, 50, 60 and 70 years. In 1983 a new cross-sectional study was carried out on the age-groups 3-80 years. The aim of the present study was to compare and analyse in detail caries prevalence and distribution in the age-groups 20-80 years at the examinations in 1973 and 1983. The subjects were examined clinically and radiographically regarding number of teeth, caries, restorations, etc. The mean number of teeth increased between 1973 and 1983, especially in the older age-groups. During the same period, the percentage of DFS decreased in the age-groups 20, 30 and 70 years, and was unchanged in the age-groups 40 to 60 years. There were only minor differences in DS in the respective age-group during the 10-year period. The distribution of subjects according to DFS showed that a large proportion of individuals in the age-groups 20 and 30 years had low DFS in 1983 as compared to 1973. For the age-group 40-years, the distribution was unchanged. For the 50, 60 and 70-year-olds, there was a change in distribution towards a larger proportion of individuals with high DFS values in 1983 as compared to 1973. The frequency distribution of individuals with primary and secondary carious lesions respectively was skewed, a small number of individuals having a high number of lesions in each age-group.(ABSTRACT TRUNCATED AT 250 WORDS)