This book constitutes the refereed proceedings of the 11th symposium of the Cross-Language Evaluation Forum, CLEF 2010, held in Padua, Italy, in September 2010 as the First International Conference on Multilingual and Multimodal Information Access Evaluation - in continuation of the popular CLEF campaigns and workshops that have run for the last decade. The 12 revised full papers presented together with 2 keynote talks and 2 panel presentations were carefully reviewed and selected from numerous submissions. The papers include advanced research into the evaluation of complex multimodal and multilingual information systems in order to support individuals, organizations, and communities who design, develop, employ, and improve such systems. The papers are organized in topical sections on resources, tools, and methods; experimental collections and datasets, and evaluation methodologies.