The aim of this paper is to analyse the scope of the non bis in idem principle in the field of administrative sanctioning law. To this end, we will first examine the concept and basis of the principle and its place within the list of fundamental rights. Subsequently, we will try to study its operation, both in its material and procedural aspects, in light of the prevalence of criminal jurisdiction over the Administration’s sanctioning power. Finally, we will examine its significance in the exclusive field of administrative sanctioning law.