Regional Trade Agreements (RTAs) have increased significantly in number over the past few years. The number of RTAs which include environmental provisions is also increasing. However, these provisions, and the experience related to their negotiation and implementation, have not been examined in depth yet. This study contributes to filling this gap. It provides an overview of approaches to environmental issues in RTAs and summarises country experiences in their negotiation and practical application. Regional and bilateral trade arrangements are surveyed, including customs unions and free trade agreements. The study is based on the analysis of RTA texts, and on literature examining their actual implementation, as well as on first-hand comments and input from experts from both OECD and non-OECD countries.