Nuclear and other radioactive materials are being trafficked illegally. These materials are likely to be used in terrorist attacks that could, given the extremely perilous nature of such substances, inflict an enormous number of casualties and many unforeseen consequences. This fact raises important issues that require precise examination of the wide variety of international legal instruments that could potentially be invoked to curb this threat. It is crucial to investigate this phenomenon and the role that can be played by international law in the fight against illicit trafficking in nuclear materials. In particular, closer examination is needed into how the law views the various actors in the nuclear black market, especially non-State actors, and which mechanisms have been set up so far in order to tackle this menace.