From the moment that their enormous destructive capacity was first shown to the world, nuclear weapons are universally considered as the most cruel weapons that exist. Nevertheless, several countries developed nuclear weapons since then. At the same time, much international efforts have been put into stopping the spread of nuclear weapons and, eventually, reaching complete nuclear disarmament. Looking in retrospective, how successful have these efforts been in the last 65 years? After a concise comparison between forecasts and outcomes of the nuclear proliferation process, this article analyses a variety of non-proliferation efforts, and also compares them to the accomplishments in the field of chemical and biological weapons.