DILS 2004 (Data Integration in the Life Sciences) is a new bioinformatics workshop 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 diverse data. Relevant data is typically distributed across many data sources on the Web and is often structured only to a limited extent. Despite new interoperability technologies such as XML and web services, integration of data is a highly difficult and still largely manual task, especially due to the high degree of semantic heterogeneity and varying data quality as well as specific application requirements.