DILS 2004 (Data Integration in the Life Sciences) is a new bioinformatics wo- shop focusing on topics related to data management and integration. It was motivated by the observation that new advances in life sciences, e. g. , molecular biology, biodiversity, drug discovery and medical research, increasingly depend on bioinformatics methods to manage and analyze vast amounts of highly - verse data. Relevant data is typically distributed across many data sources on the Web and is often structured only to a limited extent. Despite new inter- erability technologies such as XML and web services, integration of data is a highly di?cult and still largely manual task, especially due to the high degree of semantic heterogeneity and varying data quality as well as speci?c application requirements. The call for papers attracted many submissions on the workshop topics. - ter a carefulreviewing processthe internationalprogramcommittee accepted 13 long and 2 short papers which are included in this volume. They cover a wide spectrum of theoretical and practical issues including scienti?c/clinical wo- ?ows, ontologies, tools/systems, and integration techniques. DILS 2004 also f- tured two keynote presentations, by Dr. Thure Etzold (architect of the leading integration platform SRS, and president of Lion Bioscience, Cambridge, UK) and Prof. Dr. Svante Pa...abo (Director, Max Planck Institute for Evolutionary Anthropology, Leipzig). The workshop took place during March 25-26, 2004, in Leipzig, Germany, and was organized by the Interdisciplinary Bioinformatics Center (IZBI) of the Universityof Leipzig.