The article addresses the peacebuilding process in post-conflict states. It explores the approaches to the above issue of two different actors of international relations – the states and the international organizations. The activities of the United States of America and the European Union constituted an example of the involvement in this process. Both of them possess necessary resources to effectively complete extremely expensive and lengthy engagements. The United States, as a superpower, pursue its interests in various regions of the world and, because of ist political position, have sufficient resources to actively participate in the peacebuilding process. However, there exists a danger that the US may pursue ist particular interests by camouflaging them with narratives on conflict resolution and the reconstruction of post-conflict states and societies. In turn, the European Union strives to achieve the position of a superpower in international relations, increasing ist political significance. Moreover, as an international organization with political, economic and military capability, so much needed in the context of the peacebuilding process, it is predestined to be active in this area.