The author considers which form of association of EU states the Treaty establishing a Constitution for Europe reflects. The word treaty means that one has to deal with the international treaty adopted by the will resulting from equality in law of all EU states. On the other hand the word constitution expresses that the entity established by the treaty has a character which in some respects resembles to that of a state. The EU bears some features of a state - namely citizenship and symbols, nevertheless it does not have its own sovereign power because this is derived from the sovereignty of member states. The EU institutions don't present a copy of classical division of power in the state and in this context one may say that the EU doesn't have its own mechanism of enforcement of legal obligations. In the text of the treaty we don't find an explicit statement that the EU becomes a composed state. Hereafter one has to deal with the international organization with several elements of supranationality whose existence is possible and whose functionning depends on its sovereign member states. Perhaps it seems as most correct to refer to the EU by a functionalist definition.