Abstract
The article deals with the definition of criminal law as developed over the last twenty years in the Opinions presented by Advocates General before the European Court of Justice. Two notions will be identified here. The first is linked to national experiences and the need perceived by every State to protect fundamental national values, as considered in several cases in the nineties and in the first years of the new millennium. The second– now prevailing – is the outcome of the phenomenon of cross-fertilisation between the case law of the European Court of Justice and the European Court of Human Rights, and appears to relate more to the protection of human rights. The article analyses single trials, starting from 1991, and aims at finding reasons why the second notion should be preferred in a legal system such as the European Union in light of its link to the European Convention on Human Rights and the relevance of the protection of fundamental rights in the European Union legal framework.