On the basis of a thorough empirical analysis, the article comes to a number of theoretical conclusions which have never previously been discussed in the literature. In particular, it demonstrates that the Court's procedure is governed not only by ‘procedural law’ but also by norms which are non-legal. Moreover, it clearly circumscribes which norms in the documents relating to the functioning of the Court are procedural and which lack this character. In their entirety, provisions governing the Court's procedure form a ‘normative system’, with the law being only one of its elements. The Court's procedural norms originate both from the traditional sources of international law as well as from sources which, according to the usual classification, do not necessarily belong to that category. The procedural norms that are derived from all of these sources, while not tending towards uniformity in terms of their characteristics and effect, nevertheless form a system which operates as a whole. The procedure of the International Court of Justice does not fit neatly within the general scheme of ‘legal versus non-legal norms’; neither can one readily apply the theory of traditional sources of international law to a procedural system which brings together heterogeneous elements and must therefore be explained keeping in mind its own logic and nature.