The profession of real estate investment contains the activity of facility management, consultancy, expertise and planning. The professionals of real estate industries are engineers, lawyers, economist, environmentalists, etc. For the successful fulfilment of the different tasks it is essential to make data acquisition, create a decision support system. During the decision support especially in those cases when we have spatial data, the GIS can give an indispensable assistance. In the development process of real estate a kind of synergy occurs while we integrate several data bases and different knowledge which can lead us to more effective decisions and information. The decision support model contains the requirements raised by different speciality against real estate development. In the article we outline the above mentioned facts with the help of different examples.