Oryzabase contains 16,000 biological resources, including wild rice, mutants, and experimental strains, together with 4000 trait genes collected from journal articles. The database also contains genetic and genomic maps, and 20,000 items from the published literature. Of these items, the most valuable are the biological resources, particularly the wild rice and mutant collections, because they have been thoroughly characterized by researchers and are accompanied by large quantities of data. The next most valuable content is the trait gene dictionary, which has been maintained continuously since 1995 and is based on published literature. Oryzabase also plays a role as an international site for the submission of rice genes. Besides maintaining original data, Oryzabase compiles genomic data that are systematically integrated with existing data holdings and provided with a user-friendly interface. Oryzabase can be accessed at http://www.shigen.nig.ac.jp/rice/oryzabase/.