This master's thesis presents and analyzes investigative powers available to the European Public Prosecutor, with a special emphasis on their integration into the Croatian legal system. The aim of this paper is to investigate the extent to which the Croatian Criminal Procedure Act fulfills the requirements set by the Regulation of the European Parliament and the Council on the establishment of the European Public Prosecutor's Office. Moreover, the paper addresses the issue of mutual cooperation among European prosecutors in cross-border situations, highlighting that the mechanisms of collaboration they employ significantly differ from traditional mechanisms of judicial cooperation in criminal matters. Furthermore, this paper provides a detailed analysis of how the specificities of national laws and procedures often present obstacles to the effective implementation of investigative powers of the Office in cross-border situations. A thorough analysis of judicial oversight of these powers is also included, distinguishing between ex ante and ex post control. Finally, an overview of the previous practice of the European Public Prosecutor's Office in the Republic of Croatia is conducted to determine the effectiveness and any potential shortcomings in the application of investigative powers at the national level.