This book constitutes the refereed proceedings of the 25th British National Conference on Databases, BNCOD 25, held in Cardiff, UK, in July 2008.

The 14 revised full papers and 7 revised poster papers presented together with an invited contribution were carefully reviewed and selected from 45 submissions. The papers are organized in topical sections on data mining and privacy, data integration, stream and event data processing, and query processing and optimisation. The volume in addition contains 5 invited papers by leading researchers from the International Colloquium on Advances in Database Research and the two best papers from the workshop on Biodiversity Informatics: Challenges in Modelling and Managing Biodiversity Knowledge.