Description:This book constitutes the refereed proceedings of the 31st Conference on Current Trends in Theory and Practice of Computer Science, SOFSEM 2005, held in Liptovský Ján, Slovakia in January 2005. The 28 revised full papers and 16 revised short papers presented together with 8 invited contributions were carefully reviewed and selected from 144 submissions. The papers were organized in four topical tracks on foundations of computer science, modeling and searching data in the web area, software engineering, and graph drawing and discrete computational mathematics.