WormBase (http://www.wormbase.org/), the model organism database for information about Caenorhabditis elegans and related nematodes, continues to expand in breadth and depth. Over the past year, WormBase has added multiple large-scale datasets including SAGE, interactome, 3-D protein structure datasets, and NCBI KOGs in addition to an extensive intellectual lineage of the C. elegans research community. To accommodate this growth, the International WormBase Consortium has improved the user interface by adding new features to aid in navigation, visualization of large-scale data sets, advanced searching, and data mining. Internally we have restructured the database models to rationalize the representation of genes and to prepare the system to accept the genome sequences of three additional Caenorhabditis species over the coming year.