This book is about the intervention of the United Nations in armed conflicts: the case of MONUSCO in the DRC. The sacerdotal mission of the United Nations since its creation at the great conference of YALTA in 1945 is the maintenance of international peace and security in accordance with its charter. It is with this in mind that this paper focuses on the United Nations, since its inception the world has undergone a number of changes that call into question its effectiveness and primary mission. However, the sub-theme of this work revolves around the UN mission in the DRC, a country plagued by armed conflict and political instability for more than two decades, with more than 10 million dead, over a million displaced and more than 700,000 women raped. The aim is to discuss the contribution and role of the UN in intervening in armed conflicts, with a focus on the Democratic Republic of Congo.