Asian big cats (including tiger, snow leopard, clouded leopards, and subspecies of leopard, cheetah and lion) are listed in the top three categories of threat on the IUCN Red List, with illegal trade included among the threats to their survival. They are all included in CITES Appendix I, so that all international commercial trade is prohibited, although there is a sizeable international trade in captive-bred live animals, particularly tigers, which can be for commercial purposes. CITES Parties have over the years adopted, through Resolution Conf. 12.5 on Conservation of and trade in tigers and other Appendix-I Asian big cat species (last revised at the 16th meeting of the CITES Conference of the Parties [CoP16] in March 2013) (“the Resolution”) and related Decisions, a series of measures to regulate trade and promote Asian big cat conservation. This review provides background on the conservation status and illegal trade of ABCs, and identifies current best practices and continuing challenges in implementation of the Resolution, highlighting significant developments since CoP16. Much of it focuses on tigers, reflecting that the Resolution was originally developed to address tiger trade, with its particular dynamics, although information on other species is also included where possible.