The Charter of the United Nations was brought into existence in the form of an international treaty. In the course of the last fifty years, however, the "constitutional predisposition" of the Charter has been confirmed and strengthened in such a way that today the Instrument must be referred to as the constitution of the international community. In this article, the author suggests that the Charter is the constitution of the international community in ist entirety, i.e., for all subjects of international law, and that such an understanding of the Charter has significant repercussions for its legal status, interpretation, amendment, and possible future Reform. The article first discusses how the concept of a constitution has been used with regard to the modern state. The author next presents writers who have made a consistent use of "constitutional" models in international law. The article then explains why the concept of a constitution can be applied to bodies other than states and discusses the relationship between the international community and an international constitution. Next, the article distinguishes the constitutional law of the international community from "general international law", jus cogens, and obligations erga omnes. Finally, the author outlines a number of consequences of the constitutional Approach with particular emphasis placed on the admission and expulsion of members.