Fight against organized crime is a proactive, strategically oriented activity of all contemporary, democratic states, both nationally and at the international level. The set limits of more efficient suppression of the most serious crimes are the result of active reforms of national normative frameworks, ratified international documents, but also intensive professional cooperation between countries in the field of detecting, combating and prosecuting organized crime. Security threats, which are extremely high when it comes to organized crime, would be difficult to combat without adequate international cooperation between democratic states. One of the countries that actively participate in international cooperation, emphasizing cooperation with European agencies is Serbia. Namely, there is a justified question of the efficiency of Serbia's cooperation with European agencies in the suppression of organized crime, the harmonization of the national framework with the acquis communautare, which is the goal of research in this paper. In accordance with that, the author, through expert and critical analysis of normative solutions, results of practical application and valid theoretical views, analyses the subject matter from the following aspects: first, introductory considerations; second, the effectiveness of financial investigations and the Action Plan for Chapter 23; third, Serbia's cooperation with European agencies in combating organized crime and reforming the normative framework; fourth, concluding remarks.