This is a study of the relationship between the status of permanent neutrality and the modern system of collective security. The point in question is whether or not the status of permanent. Neutrality is compatible with the system of collective security which requires its members to participate in coercive measures against a common enemy. Based on a number of scholastic arguments presented in the past this is a comparative study of two different arguments : one by Switzerland which is not a member of the United Nations, and the other by Austria which has been a member of the U. N. since 1955. First, it examines these arguments in order to determine why Switzerland and Austria chose different, courses. Then, actual practices of these states in relation to the U. N. are examined in order to probe the possibility or impossibility of the existence of permanent neutrality in the United Nations. It is, then, concluded that, from a legal point of view, there remain many conditions that must be met before a permanently neutral state can become a member of the U. N. without any anxiety. But Austria became a member for her own politicalreasons, and the stability of her status in the U. N. largely depends on the political atmosphere of the organization. Whether a member of the U. N. or not, a permanently neutral state can contribute a great deal to the world peace in its own way.