Other ; The EMBL-EBI Complex Portal is a central service for information on protein complexes. We provide unique identifiers, complex members with their intra-complex binding sites and functional annotations including stoichiometry, topology, associated diseases and cross-references to the same complex in other databases. Complexes are manually curated into the IntAct database using IntAct tools, rules and quality control and are available for search and download via a dedicated website. Our unique identifiers are available for use as annotation objects in other resources, including the Gene Ontology where they can be accessed via Protein2GO. A pipeline into intermine.org enables export of organism-specific complexes to model organism resources. We have also developed a novel JavaScript visualisation tool that creates a schematic view of the topology and stoichiometry of each complex. The viewer is portable and generates the graphic on the fly. Our focus for the next two years lies in increasing content and coverage by importing ‘unreviewed’ complexes from GO, PDB and Reactome, in addition to increased manual curation, and further improving our graphical options by including 3D structural viewers as well as pathway and expression overlays. This is a collaborative project, with contributions from UniProtKB, Saccharomyces Genome Database, the UCL Gene Annotation Team, CEITEC and MINT database.