BACKGROUND: The aim of this study was to evaluate relative change over 17 years in clinical oral health outcomes inside and outside capital city areas of Australia. METHODS: Using data from the National Oral Health Survey of Australia 1987-88 and the National Survey of Adult Oral Health 2004-06, relative trends in clinical oral health outcomes inside and outside capital city areas were measured by age and gender standardized changes in the percentage of edentate people and dentate adults with less than 21 teeth, in mean numbers of decayed, missing and filled teeth, and mean DMFT index. RESULTS: There were similar reductions inside and outside capital city areas in the percentage of edentate people (capital city 63.7%, outside capital city 60.7%) and dentate people with less than 21 teeth (52.5%, 50.1%), in the mean number of missing teeth (34.3%, 34.5%), filled teeth (0.0%, increase of 5.5%), and mean DMFT index (21.2%, 19.2%). The reduction in mean number of decayed teeth was greater in capital city areas (78.0%) than outside capital city areas (50.0%). CONCLUSIONS: Trends in four of the five clinical oral health outcomes demonstrated improvements in oral health that were of a similar magnitude inside and outside capital city areas of Australia.