This book constitutes the refereed proceedings of the 29th annual European Conference on Information Retrieval Research, ECIR 2007, held in Rome, Italy in April 2007. The 42 revised full papers and 19 revised short papers presented together with 3 keynote talks and 21 poster papers were carefully reviewed and selected from 220 article submissions and 72 poster paper submissions. The papers are organized in topical sections on theory and design, efficiency, peer-to-peer networks, result merging, queries, relevance feedback, evaluation, classification and clustering, filtering, topic identification, expert finding, XML IR, Web IR, and multimedia IR.