Following a general update of the Genetic Toxicology TGs in 2015, the present Document was written to provide succinct and useful information to individuals unfamiliar with genetic toxicology testing, as well as experienced individuals wishing to obtain an overview of the recent changes that were made to the TGs during the recent round of revisions. It provides: 1) general background and historical information on the OECD genetic toxicology TGs; 2) a brief overview of the important types of genetic damage evaluated by these tests; 3) a description of the retained TGs; and 4) the issues and changes addressed therein during the revision process.