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.