International organisations play an increasingly important role in the international community. There are many types of international organisations – both in terms of their size and objectives. Within this diverse group of organisations there are a number of similar day-to-day problems with which each of them is confronted. In this course some key issues of the law of international organisations will be highlighted with the help of international judicial decisions. Special attention will be paid to issues such as membership, institutional structure, legal personality, powers, decision-making and decisions as well as privileges and immunities.