The enhanced cooperation for establishing the EPPO as a new and genuine transnational investigating framework for combating crimes affecting the financial interests of the EU promises effectiveness and a means for overcoming institutional paralysis in transnational criminal cases. The concept and future structure of this cooperation method between EU-MS allow the non-participation for MS by their own decision. On the one hand, this flexibility is a key factor of deepening integration in this field, but on the other hand, this bears significant risks for general goals and values of European integration, especially in the field of exercising jurisdiction (power of punishment) and launching criminal investigations. This flexibility has clear and visible consequences that are covered by the term as external effects of enhanced cooperation. The paper focuses – after describing and shortly examining all the possible external effects of the EPPO – on the jurisdictional issues arising from the flexibility of the enhanced cooperation in order to address the main findings in connection with the real possibility of impunity and forum shopping methods.