This research is an attempt to understand the extent to which the European Union (EU) and the North Atlantic Treaty Organisation (NATO) played a constructive role along the UN in resolving the conflict in Former Yugoslavia. The study establishes the case for the involvement of these regional organisations, and the major reasons for their involvement are drawn from legal, geopolitical, humanitarian and security basis as well as the failure of the United Nations Organisation to resolve the conflict. Regional organisations are bound by the UN charter to resolve conflicts peacefully1 before involving the UN. The UN could only get involved if the continuation of the conflict posed a threat to international peace and security.2 But it is the duty of the UN to ensure peace and security and since regional organisations turn to it in case of failure to resolve a conflict, then it must have the capacity to do so. But for the case of Yugoslavia the UN was hand capped because it cannot deal with internal conflicts as it is not supposed to interfere in the internal affairs of states3 to enforce peace..