It has been hypothesised that deprived neighbourhoods have poorer quality food environments which may promote the development of obesity. We investigated associations between area deprivation and the location of the four largest fast-food chains in Scotland and England. We found statistically significant increases in density of outlets from more affluent to more deprived areas for each individual fast-food chain and all chains combined. These results provide support for a 'concentration' effect whereby plausible health-damaging environmental risk factors for obesity appear to be 'concentrated' in more deprived areas of England and Scotland.