Abstract. The article highlights the history of radiological weapons ban negotiations. In 1948, the United Nations Commission on Conventional Armaments identified radiological weapons as WMD. Since as early as the 1960s, some states have put forward proposals to ban radiological weapons at the international level as potentially threatening human lives and the environment. In 1977 to 1979, a treaty banning radiological weapons was approved on the basis of a draft developed at bilateral Soviet-American negotiations in Geneva, which could have become an important impetus for further actions in limiting the arms race. The careful preparation of the text of the future treaty by the USSR and US delegations raised expectations that its finalisation by the Disarmament Commission would not take much time. The reality, however, was far different. In December 1979, the Afghan war broke out. In response to the Soviet aggression against Afghanistan, the United States took a whole set of measures, including the refusal to continue bilateral talks on the prohibition of radiological weapons. The author notes that control over radioactive materials was strengthened at the national level, without waiting for an international legal definition of radiological weapons. Political ambitions of a number of countries have prevented the Conference on Disarmament from achieving positive results. The author emphasises that today nuclear terrorism is regarded by world leaders as an urgent global-scale security threat, as confirmed by the international Nuclear Security Summit in Washington, D.C. in 2016, attended by delegations from over 50 countries. The author states that the issue of the radiological weapons prohibition remains pending. Keywords: radiological weapons, Conference on Disarmament, Ukrainian diplomatic history, USA, Geneva, USSR.