For the seventy years of its activities the United Nations demonstrated as strengths, so weaknesses. For the first four decades the UN really sought to function as an International Institute for peace and security, but in the last three decades, its achievements were insignificant; negative here prevailed over positive and, in some cases, the UN just helplessly looked at some violations of international law by its members. The states, on whose initiative the UN has been established, do no longer reckon with it. Why is this happening and how would be changed the situation for the better? The article contains answers to these questions. According to the author, the main reasons for the inability of the UN are its obsolescence and the narrowness the Institute’s foundation (discrepancy between the purposes for which it was established, and the demands of the times of the late 20th - early 21st centuries), the lack of procedures for determining the constitutional foundations of the Institute as well as contradictions between certain provisions of the Charter of the United Nations and the reality. Reformation of the Global Institute for peace and security should not be occurred by decisions of the Institute itself, but at the International Conference of the representatives of all peoples and States of the world with a genuine guarantee of their equal rights. The structure of the governing bodies and of their authorities should be defined, firstly, in accordance with the theory of democracy, and secondly, with the real challenges of humankind in the twenty-first century.