In this paper we present the use of open source tools and technologies in information system development process at the Faculty of Sciences in Novi Sad. We describe specific conditions in which this information system is being developed, and present its architecture in detail. In addition, we give an overview and present the way in which we used the most important technology in the implementation of this system - EJB 3.0 and describe specific open source tools used in the implementation processes. Finally, we present our conclusions and generalize them to all information systems developed in similar environments.