In the past, the accepted method of plan making was to survey the area, analyse its problems, and produce a plan which described a state of affairs expected at some future date. The new theories adopted a continuous, cyclical systems approach based on the identification of needs and goals, the formulation and evaluation of alternative courses of actions and monitoring of adopted programmes. This process clearly requires planning to improve its ability to use information system. In Malaysia, changes to the planning legislation favour the new approach, however, there is no adequate information system to aid the process. The implications of using Geographical Information Systems for planning at the municipal level are examined in this study, initially, with reference to Kuala Lumpur as a whole but more specifically, with reference to a detailed case study of planning for the management of squatter problems. After the initial development of the GIS database, it is used to evaluate the existing characteristics of the Jinjang/Kepong Squatter Settlement. Subsequently, a number of scenarios are developed which take into account the socio-economic characteristics of the squatters, the constraints of the physical layout of existing squatter settlements, availability of land and site suitability for different kinds of development. Spatial modelling techniques are employed to examine alternative plans for the squatter areas. These plans are evaluated using cost-benefit analysis incorporated into the GIS database.