The subject matter of this thesis is combating money laundering and the financing of terrorism. As criminal activity, money laundering is not only one of the most widespread criminal acts because of its scope of organization, sophistication, diversity of execution methods and international character, but also one of the most dangerous nowadays, considering various negative consequences it inflicts upon economic development of a certain country, as well as those of transnational character, specifically, due to the aforementioned properties. One of the main negative transnational money laundering effects is undoubtedly its facilitation of the financing of terrorist organizations which are oriented towards concealing ultimate purpose of the financial resources, unlike criminal groups, whose primary objective lies in concealing the origin of financial funds. Regardless of their mutual differences, the international community recognized intertwined nature of money laundering and the financing of terrorism. The issue of money laundering through its fundamental features will be analyzed foremost in this thesis, furthermore building on the issue of the financing of terrorism, notably, types of assets and their methods of transfer, ie the supply methods of the terrorist organizations. In so doing, particular focus is on the importance of the international community endeavours to counter money laundering and the financing of terrorism, since each of these criminal activities endangers the values protected by norms of international law. In this regard, the aforesaid is best outlined through the established international legal instruments under the auspices of the United Nations, as well as within the European Union. Additionally, the significance of the related issue is examined through the contribution and influence of other international organizations in the field of money laundering and the financing of terrorism prevention, such as FATF and MONEYVAL, alongside those already mentioned.