This study investigates population mobility and its relationship with area level deprivation and health. Based on UK movement in the year preceding the 2001 census, small areas in Scotland were classified as being one of the following population types; decreasing, increasing or stable (with high or low turnover). In the most deprived areas, illness rates for those under 65 were significantly lower in stable populations with low turnover than in other areas of comparable deprivation. Decreasing populations in deprived areas had significantly highest illness rates overall. Leaving those in poor health behind may lead to artifactual increases in area based health inequalities.