The discussion here traces the emergence of the body of policy and rules now collected under the heading ‘EU criminal law’ from its historical multi-level origins to its present location in the EU’s Area of Freedom, Security and Justice, focussing on the developing legislative competence and significant reliance on the strategy of mutual recognition to achieve progress in this context. At the same time, it is necessary to consider how legislation and judicial activity in this field relates to the operational aspects of a number of EU criminal justice agencies, in particular OLAF, Europol and Eurojust. However, questions remain concerning the identity and role of EU criminal law: whether it should be seen as a regional mechanism for the transnational control of human mobility, or whether it comprises a genuinely distinctive and new articulation of European values in criminal law and criminal justice