Abstract The purpose of this article to critically analyse the core EU principles applicable to transnational organized crime: approximation of national laws and procedures, mutual recognition of judicial decisions and the principle of availability. These principles have been instrumental in closing various gaps created by divergence of criminal laws and justice systems among Member States and in promoting a common EU approach to the problem. Member States have also become more willing to implement measures such as framework decisions at the national level. These principles are explicitly or implicitly mentioned under the TEU and TFEU and therefore their legitimacy has been recognized under the current European legal framework. Nevertheless, it will be shown that a variety of problems, such as State sovereignty, a lack of due regard for protection of human rights, enlargement, and other practical difficulties are simultaneously affecting the ability of the EU and Member States to prevent and suppress the practice effectively. It is further argued that a criminal justice response to transnational organized crime on its own is not sufficient, and that the EU and Member States must address wider issues such as the supply of, and demand for, illicit goods and services.