The aim of the present investigation is to report on the trends in the prevalence and severity of dental caries and dental status in an adult Swedish population over a 30-year period (1973-2003). Four cross-sectional epidemiological studies in 1973, 1983, 1993, and 2003 were performed in Jönköping, Sweden.A random sample of individuals aged 20, 30, 40, 50, 60, 70, and 80 years were examined clinically and radiographically, a total of 2521 individals. Diagnostic variables were edentulousness, number of teeth, initial and manifest caries lesions, restorations, fissure sealants, and quality of restorations (secondary caries and overhangs). The percentage of edentulous 40- to 70-year-old individuals decreased during the 30-year period from 16% to 1%. The distribution of individuals by DFS in the age groups 20-50 years showed a gradual shift towards a positively skewed distribution between the years 1973 to 2003. There was a steady decrease in mean number of DFS in the age groups 20-50 years. In the 20-year-olds the mean number of DFS decreased by 72% and for 50-year-olds, by 37%. In conclusion there has been a marked decrease in DFS in adults up to middle age and a marked reduction in edentulousness over a thirty year period. This shows that the decrease in caries levels in children and adolescents is also occurring among adults.