Until recently, the development of Geographical Information Systems (GIS) concerns primarily spatially-oriented database management. Many of such resulting GIS reached remarkable levels of sophistication, although they lacked tools to support decision making. In some literature new directions can be read. Partly because they describe GIS as Decision Support Systems (DSS), partly because more comprehensive developments attached to available GIS are mentioned. Discussions on GIS and DSS have been taking place in The Netherlands during the last 2 or 3 years. Perhaps as a result of those discussions, the Royal Planning Department of the Dutch Ministry of Housing, Planning, and Environment requested the development of some initial tools of decision support on behalf of the Dutch Spatial Information System called RIA. Conceptualization of the approach of decision support led to a system with a more general usability. Data handlings are strongly related to the available geographical information, although included analysis tools consist ofgeo-statistical analysis, as well as of tools which are dedicated to inform decisionmakers during the spatial decisionmaking process. With special attention to user interfacing, an integrated GSS and DSS has been worked out, and the first results can be demonstrated.