The folates are a group of heterocyclic compounds based on the 4-[(pteridin-6-ylmethyl)amino]benzoic acid skeleton conjugated with one or more L-glutamate units. The document is a revision of recommendations prepared by the IUPAC-IUB Commission on Biochemical Nomenclature in 1964. The main changes are a consequence of the much greater information that now exists about the stereochemistry of folates. Recommendations on the nomenclature of reduced compounds and substituents are included, as are proposed symbols and abbreviations.