NEWT is a new taxonomy portal to the SWISS-PROT protein sequence knowledgebase. It contains taxonomy data, which is updated daily, for the complete set of species represented in SWISS-PROT, as well as those stored at the NCBI. Users can navigate through the taxonomy tree and access corresponding SWISS-PROT protein entries. In addition, a manually curated selection of external links allows access to specific information on selected species. NEWT is available at http://www.ebi.ac.uk/newt/.