The Green Customs Guide provides information and guidance to Customs and other border control officers to assist in their efforts to monitor and facilitate the legal trade and to detect and prevent the illegal trade in environmentally sensitive commodities such as ozone depleting substances, toxic chemicals, hazardous waste, endangered species and living modified organisms. This Guide explains the Green Customs Initiative and provides an overview of the relevant trade-related treaties and organisations that are included in this Initiative. Information is provided on how trade is regulated and the responsibilities of Customs officers in implementing the various controls are described. Specialised terminology is explained and sources of further information and assistance is provided. The Guide is designed to be used as part of a training curriculum for customs officers or as a stand-alone resource.