This book constitutes the thoroughly refereed post-proceedings of the Third International Workshop of the Initiative for the Evaluation of XML Retrieval, INEX 2004, held in Dagstuhl Castle, Germany in December 2004. The 33 revised full papers presented together with an introductory overview of the INEX campaign were carefully selected for presentation at the workshop and went through a subsequent round of careful reviewing and revision. The papers are organized in topical sections on methodology, ad hoc retrieval, ad hoc retrieval and relevance feedback, relevance feedback, ad hoc retrieval and heterogeneous document collections, heterogeneous document collections, natural language processing, and ineractive studies.