Evaluating the effectiveness of nuclear export controls necessitates a serious analysis of the circumstances in which they function and the elements that give them force, such as the international non-proliferation legal context, legal aspects of the regimes’ organisation and the national implementation of the guidelines agreed to by regime members. This paper analyses the relevant nuclear law related to nuclear export controls by evaluating sources of international nuclear law as well as the structure and activities of the two international nuclear export control regimes, the Nuclear Suppliers Group and the Zangger Committee.