This book constitutes the refereed proceedings of the Second International Workshop on Data Integration in the Life Sciences, DILS 2005, held in San Diego, CA, USA in July 2005.

The 20 revised full papers presented together with 8 revised posters and demonstration papers, 2 keynote articles and 5 invited position statements were carefully reviewed and selected from 50 initial submissions. The papers are organized in topical sections on user applications, ontologies, data integration, and others and address all current issues in data integration from the life science point of view.