Regulation 2017/1939 sets up the European Public Prosecutor’s Office (EPPO) on the basis of enhanced cooperation. This new EU body, organised at a central and decentralised level, should enhance the protection of the EU budget through criminal law. While this is a shared competence (Art. 325 TFEU), the EU Commission pushed for the creation of EPPO, dissatisfied with national enforcement efforts. EPPO thus emerges from a feeling of distrust toward the Member States. Yet to achieve its goal, EPPO will need to rely on existing national authorities (eg police, customs, judges) and domestic law. European delegated prosecutors will also be part of the national public prosecutor’s office, while being hierarchically subordinated to the central office. Loyal cooperation and mutual trust (eg in sharing information) will thus be crucial. This paper aims to exam vectors of trust and distrust in EPPO’s structure and the rules on its functioning to make proposals for its operational success.