The private-rented sector (PRS) in Northern Ireland has witnessed a decline formost of the twentieth century. At the beginning of the last century approximately90% of households rented privately, but by 1991 only 5% of the total stock wasprivately rented, representing 28,600 dwellings. However, since 1991 the sector hassteadily increased, and by 2004 the PRS represented 9.2% (62,500 dwellings) ofthe total dwelling stock, an increase of 120%. In Britain, there has been much debate about the residualisation of council housing with a focus on how lower income households have been increasingly located in council housing with the more affluent being encouraged into owner occupation changing the social profile of council housing. This article, however, will seek to examine the impact the recent growth of the PRS has had on the socio-economic profile of housing estates in Northern Ireland and the tenure transfer that has taken place within these estates. The article examines current trends inthe more ‘settled’ housing estates in Northern Ireland, and argues that a processof residualisation is emerging within these areas as a result of the changing natureof the PRS.