The article deals with the prevention aspect of the concept of Responsibility to Protect. The analysis performed by the author covers the most important R2P documents. The author presents the intergovernmental debate that took place mainly at the UN General Assembly, as well as the evolution of the approach of the UN institutions to R2P and the growing acceptance of the development of the prevention aspect. The article systematises and analyses the international instruments of prevention of mass atrocities: early warning, preventive diplomacy, economic and military instruments. Moreover, it identifies the main difficulties experienced by countries and international organisations that have decided to take action towards preventing mass atrocities.