The PSI-MI (Molecular Interactions) CV was first published in 2004 and, since then, has been regularly extended to encompass new experimental methodologies and to serve extensions made to the formats to accommodate new data types. The CV is maintained on GitHub () and is readily available through the Ontology Lookup Service (www.ebi.ac.uk/ols/ontologies/mi) and BioPortal (). An issue tracker on GitHub enables new term or update requests to be submitted by the user community. Use of the PSI-MI CV is an integral step in describing interaction data using the PSI-MI formats.