Gene Ontology (GO) vocabularies are an established standard for linking functional information to genes and gene products (www.geneontology.org/). A recent collaboration between University College London and the European Bioinformatics Institute is providing GO annotation to human cardiovascular-associated genes (http://www.ucl.ac.uk/medicine/cardiovascular-genetics/geneontology.html). This report outlines the aims of this collaboration and summarizes how the cardiovascular community can help improve the quality and quantity of GO annotations. This new initiative is funded by the British Heart Foundation and fully supported by the GO Consortium.