AIM: The present investigation presents findings of the prevalence and distribution of gingivitis and periodontitis in a Swedish population over the 30 years 1973-2003. MATERIAL AND METHODS: Four cross-sectional epidemiological studies in 1973, 1983, 1993, and 2003 were performed in Jönköping, Sweden. Random samples of individuals aged 20, 30, 40, 50, 60, 70, and 80 years were examined clinically and radiographically. Diagnostic criteria were edentulousness, number of teeth, plaque, gingival status, probing pocket depth, gingival recession, alveolar bone level, and classification according to periodontal disease status. RESULTS: In all age groups, the number of edentulous individuals decreased dramatically and the number of teeth increased. Oral hygiene improved considerably. Over the 30 years, the proportion of periodontally healthy individuals increased from 8% in 1973 to 44% in 2003 and the proportion of individuals with gingivitis and moderate periodontitis decreased. There was a non-significant trend for the proportion of individuals with severe periodontal disease experience (Group 4) to decrease, while the proportion of individuals with advanced periodontitis (Group 5) remained unchanged. CONCLUSION: Oral hygiene and periodontal health improved significantly in the 20-80-year age groups over the 30 years 1973-2003.