This volume contains the proceedings of the Fourth International Conference on Advances in Information Systems (ADVIS) held in Izmir, Turkey, October, 18-20, 2006. This is the fourth conference dedicated to the memory of Professor Esen Ozkarahan, who was one of the pioneers of database machine research and a founder of database systems in Turkey. The main goal of the conference is to bring together researchers from all around the world working in di?erent areas of information systems to share new ideas and represent their latest results. This time we received 120 submissions from 27...