This chapter deals with the important security issue of nuclear weapons and nuclear disarmament. According to a number of top security experts, climate change and nuclear weapons are the two main and most serious security risks of our time. The chapter deals with the world's nuclear arsenals and the list of nuclear-weapon states according to the prestigious Stockholm International Peace Research Institute and the latest yearbook 2023. A separate section is devoted to international treaties and agreements dealing with nuclear disarmament, and special attention is paid to the current UN International Treaty on the Prohibition of Nuclear Weapons (2017), according to which nuclear weapons are currently illegal from January 22, 2021 under international law. The positions of the nuclear powers of the USA and the Russian Federation and other owners of nuclear weapons are presented. The possibility of a local nuclear conflict, which could escalate into a global catastrophe, is discussed. The next part is devoted to zones without nuclear weapons. The authors of the chapter present their own ideas and recommendations for reducing the danger of nuclear weapons and speeding up and making nuclear disarmament more efficient. Finally, the International Campaing to Abolish Nuclear Weapons organization, which won the 2017 Nobel Peace Prize, is shortly introduced.