This study looks at the effects of residential -commercial land use changes on formal housing stock, in Lusaka city. This research focus on the areas in the city, which are closer to the central business district, or town centre like Rhodes Park, Fair View, Northmead, and Thorn Park, where it has been observed, that there are continuous changes in residential land use to various uses, especially to commercial uses. There is noticeable spread of economic activities along the major roads in Lusaka such as; Addis Ababa Avenue, Independence Avenue, Church Road, Makishi road, Great East road, Bwinjifumu Avenue, and Katima Mulilo Road. The main cause of this is that the central business district of Lusaka has failed to contain the ever increasing demand of office space, traffic congestion and inadequate parking space thus prompting companies to move into the residential areas. Economic theory actually supports this trend when it suggests that as economic activities are expanding in thecity, other areas close to the CBD have to be absorbed to accommodate the trend.Many residential houses and bare plots are being steadily converted into Commercial use, mostly for office use purposes.