This updated version of IAEA Nuclear Security Series No. 9, Security of Radioactive Material in Transport, is intended to facilitate the establishment of an internationally consistent approach to security of radioactive material in transport. It builds on the relevant recommendations of various existing IAEA Nuclear Security Series publications and is applicable to the security of packages containing radioactive material that could cause unacceptable radiological consequences if used in a malicious act during international or domestic transport. It is also relevant to the security of some nuclear materials of category III and below during transport, due to the radioactive nature of the material. Guidance on protection against unauthorized removal and sabotage is also covered.