The series of ISCIS (International Symposium on Computer and Information Sciences) symposia have been held each year since 1986, mostly in Turkey and occasionally abroad. It is the main computer science and engineering meeting organized by Turkish academics and was founded by Erol Gelenbe. Each year ISCIS attracts a significant number of international participants from all over the world. The 19th ISCIS was organized by Bilkent University, Department of Computer Engineering, and was held in Kemer-Antalya, Turkey during 27–29 October 2004. For ISCIS 2004, a total of 335 papers went through the review process and a large number of high-quality papers competed for acceptance. This volume of the Springer Lecture Notes in Computer Science (LNCS) series contains 100 of those papers that broadly fall into the following areas of interest: artificial int- ligence and machine learning, computer graphics and user interfaces, computer networksand security, computer vision and image processing,databasesystems, modeling and performance evaluation, natural languageprocessing, parallel and distributed computing, real-time control applications, software engineering and programming systems, and theory of computing.