The title of my lecture is obviously over ambitious. The case law of the European Court of Justice (ECJ) concerning environmental issues is quantitatively and qualitatively vast. On a rough estimate, it includes more than 700 judgments relating to over 50 different Community legislative acts that directly or indirectly regulate environmental matters, as well as national measures in the field, general principles and Treaty provisions. For these reasons, I focus on two topics. The first area relates to what is perhaps the key task of the ECJ in this area: balancing the often conflicting requirements of market integration with those of environmental protection, both at national and at Community level. I discuss the most relevant decisions of the ECJ in this field to work out the pattern, if any, which emerges. From this case law, we may also be able to discover some of the key elements of the ECJ’s overall environmental stance. I then move on to discuss some more general aspects of the ECJ’s functions and the special role of the ECJ in the enforcement of Community environmental policy.