Despite almost universal recognition within the international community of the importance of international environmental law, many complex issues continue to elude an appropriate legal response. A particularly controversial issue – and one that is proving increasingly difficult to resolve – is the question of how to reconcile the principle of environmental protection with that of free trade. Moreover, despite such positive platitudes as that contained within the 1992 Rio Declaration on Environment and Development, nation states are quickly discovering that the issue is not simply one of abstract interest, but is actually beginning to influence both their domestic and international regulatory behaviour. This article seeks to present a broad overview of this issue as it relates to the European Union (EU) and the World Trade Organization (WTO). In particular, the article will critically discuss some of the more recent jurisprudence on this issue arising from these two, very different, ‘groupings’ of states. As will be noted, there are important similarities and differences between each ‘grouping’ in terms of its approach. And, of course, whilst it is acknowledged that many of these differences can be resolved by reference to the different aims and objectives of the different ‘groupings’, nevertheless, this article will try to move beyond a strictly comparative approach of the issues, and place them in a broader analytical framework. This is not an attempt to show which approach is ‘best’, but rather, to highlight the tensions between environmental protection and free trade.