This book constitutes the refereed proceedings of the 28th European Conference on Information Retrieval Research, ECIR 2006, held in London, April 2006. The 37 revised full papers and 28 revised poster papers presented are organized in topical sections on formal models, document and query representation and text understanding, topic identification and news retrieval, clustering and classification, refinement and feedback, performance and peer-to-peer networks, Web search, cross-language retrieval, genomic IR, and much more.