This book constitutes the refereed proceedings of the 10th International Conference on Database Theory, ICDT 2005, held in Edinburgh, UK in January 2005.The 24 revised full papers presented together with 3 invited articles were carefully reviewed and selected from 84 submissions. The papers are organized in topical sections on query languages and types, multi-dimensional data processing, algorithmic aspects, privacy and security, logic and databases, query rewriting, and query processing and data streams.