The aim of this paper is to use Geographical Information Systems (GIS) in defining and analysing the catchment area of retail centres. The first part of the paper presents a review of some existing retail centres and discusses their catchment sizes and extents. In addition, the paper defines some of the GIS functions, which can be used for retail catchment applications. In order to use GIS for retail catchment analysis, a retail centre called Al-Dawly Centre located at Jeddah City, Saudi Arabia is selected as a case study. Two types of GIS-based retail catchment models are produced for this centre. The first model is created based on customers' distribution and the second model is produced based on drive-time technique. Each one of these catchment models is used further for market analysis and demand identification purposes.