This Safety Guide will aid regulatory bodies and users of radioactive material. It provides the relevant requirements as detailed in IAEA Safety Standards Series No. SSR-6 (Rev. 1) as applicable to the type of radioactive material, package or shipment. Once a consignor has properly classified the radioactive material to be shipped (following the recommendations provided in this Safety Guide), the appropriate UN number can be assigned and the paragraph numbers of specific requirements for shipment can be found in the corresponding schedule. This publication supersedes IAEA Safety Standards Series No. SSG-33, issued in 2015.