This chapter aims at discussing the need of the establishment of a Convention on Radiological Security. In this chapter the words "radiological security" cover the security of radiation sources as defined in the 2003 edition of the Code of Conduct, which would generally make it a subgroup of nuclear security. The categorization includes a "plain language" definition with a distinction between individual source and dispersed radioactive material occurrence. These are the three typically considered radiological weapons, which unlike nuclear weapons do not produce a nuclear chain reaction and hence no massive explosion. The provisions of the Code are not applicable to unsealed radioactive materials, radioactive sources used for military purposes, and nuclear materials. The Code of Conduct was completed in 2004 by the Guidance on the Import and Export of Radioactive Sources aiming at reinforcing radiological security during imports and exports of radioactive sources.