This thesis studies the peacekeeping, peace enforcement and peace-building efforts undertaken by the United Nations (UN) in the Congo. Part one investigates the UN mission in Congo 1960 to 1964 and the second part looks at the current mission that started in 1999 which is currently ongoing. The final part makes a comparative analysis of the two case studies. Peacekeeping, peace enforcement and peace-building are some of the approaches the UN uses in order to manage and settle conflict. While these concepts are often related to one another, they possess certain characteristics making them distinguishable. I solemnly use these concepts when conducting the two case studies and the comparative analysis. I study the mandates as well as the activities in the field. My main argument is that while the mandates differed between the two peace operations, the actual activities in the field shared many common features. I will show that the first peace operation in the Congo deviated from all others undertaken by the UN thus far. The Congo crisis in the sixties took place at the height of the Cold War. What commenced as a traditional peacekeeping operation eventually turned into a mission of peace enforcement. These enforcement measures were never supported by a Chapter VII mandate. There were also elements of peace-building efforts such as trying to install functioning governmental institutions. As such, it deviated from other peace operations during that time. Although these are considered as pioneering for many current peacebuilding missions, they cannot be considered as broad as today’s efforts. The current peace operation in Congo also started as a peacekeeping operation. As the conflict escalated, a Chapter VII mandate was provided to use force. Similarly to the peace operation during the Cold War, it also went from a peacekeeping operation to one of peace enforcement. However, the ongoing peace operation is provided with much clearer and less arbitrary mandates. The peace-building efforts are also much broader. Central to the mission is to aid in the implementation of a democratic system that will survive once the peace operation has ended. These forms of efforts are quite typical since the end of the Cold War.