This chapter addresses the EU’s policy in the field of procedural criminal law. It sketches how issues similar to those discussed in the field of substantive criminal law can arise in the field of procedural law and argues that they should also be studied from within multiple disciplines. It tentatively proposes that a more evidence- based understanding of the exercise of competences in this field is a feasible model to restrain illegitimate ‘competence creep’ from the EU legislator.