Perhaps the most difficult question to answers, which, in some ways is a preliminary question, is: what exactly is an international organization? The short answer is, quite simply, that we do not know. We may, in most cases, be able to recognize an international organization when we see one, but it has so far appeared impossible to actually define such organizations in a comprehensive way.

It is common in the literature to delimit international organizations in at least some ways. One delimitation often made depends on the nature of the body of law governing the activities of the organization. If those activities are governed by international law, we speak of an international organization proper, or at least of an intergovernmental organization. If those activities are, however, governed by some domestic law, we usually say that the organization in question is a non-governmental organization; examples include such entities as Greenpeace or Amnesty International. While the activities of such entities may be international in character and they may even have been given some tasks under international law, they do not meet the usual understanding of what constitutes an international organization.

An international organization has been defined “as a forum of co-operation of sovereign states based on multilateral international organizations and comprising of a relatively stable range of participants, the fundamental feature of which is the existence of permanent organs with definite competences and powers acting for the carrying out of common aims.

In the widest sense, international organization can be defined as “a process of organizing the growing complexity of international relations; international organizations are the institutions which represent the phase of that process. They are the expressions of and contributors to the process of international organization, as well as, the significant factors in contemporary world affairs.” Further” international organizations, as institutions may come  and go in accordance with the significance of the dynamism of international  relations. But international organization, the process, exists as an established trend. It was   the stimulus of the existing process ready   at hand  that automatically led, after the collapse of the League of Nations, to the creation of new organizations like the U.N. Thus, international organization is the process by which states establish and develop format and continuing institutional structures for the conduct of certain aspects of their relationships with each other. It represents a reaction to the extreme decentralization of the traditional system of international relations and the constantly increasing complexities of the interdependence of states’’

Following are the essentials of international organization, the institution:

I.  Its origin is based on multilateral international agreement.

II.  The institution has a personality of its own, which is distinct from that of its individual members

III.  It has permanent organs which carry out common aims.

As compared to the will of all members, its organs exhibit autonomy of will.

For the international lawyer, it goes without saying that the activities of those organizations that are subject to international law will be of most interest. Usually, those organizations will have a number of characteristics in common although, in conformity with the fact that their founding fathers are relatively free to establish whatever they wish, those characteristics are not more than characteristics. The fact that they do not always hold true does not, as such, deny their value in general.

One of those characteristics is that international organizations are usually created between states, or rather, as states themselves are abstractions, by duly authorized representatives of states. This, however, doesn’t tell the whole story. For one thing, there are international organizations which are themselves members of another international organization and sometimes even founding members. The EC, thus, is a member of the FAO, and a founding member of the WTO. Still, we do not exclude the WTO and the FAO from the scope of international organizations simply because they count another organization among their members. Generally, then, it is not a hard and fast rule that international organizations can only be created by states.

Secondly, not all such organizations created by states are generally considered international organizations. States may, for example establish a legal person under some domestic legal system. Perhaps an example is the Basle-Milhouse Air-port authority, a joint venture, between France and Switzerland and governed French law.

Moreover, sometimes treaties are to be implemented with the help of one or more organs. For instance, the European Court of Human Rights is entrusted with supervising the implementation of the European Convention on Human rights. Yet, the Court is not considered to be an international organization in its own right; it is, instead, often referred to as a treaty organ.

In what exactly the distinction between an organization and treaty organ resides is unclear, and perhaps it may be argued that its importance is diminishing at any rate: scholars writing in the field of, for example environmental law, have more or less started to unite the two forms of cooperation, and use the rather generic term of “international intuitions”, as encompassing both treaty organs and international organizations. Others have pointed out that treaty organs endowed with  decision- making powers may well be international organizations in disguise,  and , in the political science literature, reference is often made to ‘international regimes’  or, again, ‘institutions’.

A second characteristic which many organizations (but again, not all) have in common is that they are established by means of a treaty, their creation was not brought about by some legal act under some domestic legal system, but was done in the form of a treaty, which international law in general terms defines as a written agreement, governed by international law. And as the treaty will be governed by international law, so too will the organization.

Not all organizations derive directly from a treaty, though. Some have been created not by treaty, but by the legal act of an already existing organization. The united Nations general Assembly, for instance has created several organizations by resolution: the united Nations industrial Development organization (UNIDO) and the United Nations children’s fund (UNICEF) come to mind, as do various institutions set up by the Nordic Council, including financial institutions such as the Nordic Investment Bank.  Indeed, the Nordic Council itself originated as a form of cooperation between the parliaments of the five sates concerned (Denmark, Finland, Iceland, Norway and Sweden), rather than being clearly treaty-based. The importance of this characteristic, then is above all to indicate that the creation of an international organizations is an intentional act. Organizations rest upon conscious decisions of the states involved; they do not come out of the blue, and are not created by accident.

That said, a describable recent tendency is to remain nebulous about intentions when creating international institutions. In recent years, organizations such as the organization for security and Co-operation in Europe (OSCE), Asia- pacific Economic Co-operation (APEC), the Arctic Council and the Wassenaar Arrangement have been established, but with all of them it remains unclear whether they indeed are to be regarded as full-blown organizations rater than, say, frameworks for occasional diplomacy, and even whether their constituent agreements constitute treaties or not. The legal status and structure of the European Union have, likewise, been subject to debate, and the G-7(or -8; the confusion is telling in itself) defies any attempt at a definition and classification.

In order to distinguish the international organization from other forms of international cooperation, another often-mentioned characteristic holds that the organization must posses at least one organ which has a will distinct from the will of its member states. Where the collectivity merely expresses the aggregate opinion of its members, giving it the legal form of an international organization would, in the extreme, be a useless act. One might as well have appointed a spokesperson.

Important though the characteristic of a ‘distinct will’ is, it is also the most difficult in terms of both practice and theory .As several authorities have noted, in practice not all organizations usually referred to as international organizations possess this characteristic. In heretical terms, the characteristic of the distinct will goes to the heart of the entire concept of international organization: the problematic relationship between the organization and its member states.

In one way, an international organization is little more than the tool in the hands of the member states, and viewed from this perspective, the distinct will of the organization is little more than a legal fiction. Yet, the international organization, in order to justify its raison d'être and is somewhat special status international law, must insist on having such a distinct will. For, otherwise, it becomes indistinguishable from other forms of cooperate, and if so, it will become extremely difficult to justify why, for example, the constituent treaties of organizations warrant teleological interpretation, as is so often claimed, or why such constituent treaties appear to possess far greater possibilities for deriving implied clauses (in the form of implied powers) from them than regular treaties are said to do.