The aim of the study was to answer the question whether there are universal norms of customary international law governing the immunity of international organisations and their property and address the obstacles to the development of the UN Convention governing the immunity of international organisations. Through comparative legal analysis, the Author proves that state immunities result from international and national laws. In the case of immunities derived from international law, there are no universal standards defining the scope of the jurisdiction immunity of a state and its property. Jurisdictional immunity of international organisations has as its only source international law (many states also regulate the issue in their domestic law). The study showed that international regulations move in contradictory directions: as regards the states, there is a move away from absolute immunity, while for international organisations the expansion of the catalogue of authorized immunity and its scope is observed.