To date, research on the socio-economic characteristics of the social renting population in the Republic of Ireland has focused on the national level and has found that in common with many other Western European countries the years since the mid-1980s have seen an increased concentration of low income and socially excluded households in this tenure. Drawing on data on the incomes and socio-demographic status of the households who rent their dwellings from Ireland's largest social landlord, Dublin City Council, this paper explores the impact of this macro-process of residualisation on tenants in this region, and also on different localities within it. It demonstrates that residualisation has resulted in higher concentrations of poor households in social rented accommodation in Dublin compared to the general social renting population of the country and at the micro-level has impacted differently on different districts of the city and contemplates the factors which have contributed to this uneven pattern of residualisation.