Functional genomics research is producing large amounts of data on the functions of individual genes related to symbiosis. We have developed a relational database, NodMutDB (Nodulation Mutant Database), to provide a comprehensive resource for depositing, organizing and retrieving information on symbiosis-related genes, mutants and published literature. NodMutDB brings together new studies and existing mutant-based literature to facilitate our understanding of how genes function in symbiotic processes in both Rhizobia and their host plants.