An important issue in Dutch retail planning practice is prediction of the likely impacts of new retail developments on consumer demand and assessment of the feasibility of new projects. In practice, a planning team has to decide which retail plan out of a number of alternative plans has to be implemented. A decision support system for retail planning can facilitate this decision. The decision support system we are proposing consists of three modules. The first module is used to manage the required data. The second module is used to model consumer choice behaviour. This module also contains the program GIANT, which can be considered as an expert system to assist the analyst in constructing and analysing conjoint-based simulator systems. The third module summarizes and evaluates the predicted impacts of the alternative retail plans.