On May 8, 2016, the amendment to the Convention on the Physical Protection of Nuclear Material (“CPPNM”) , (“CPPNM Amendment”) entered into force. The CPPNM Amendment revises the CPPNM by seeking to further strengthen the international legal basis for nuclear security, including through applying physical protection levels to nuclear facilities. This publication explains the background to the CPPNM Amendment, as well as summarizes some of its main provisions and its impact on contracting parties. It also considers the concepts and standards enshrined in the CPPNM Amendment that warrant attention by nuclear licensees, their contractors and financial institutions doing business in the nuclear sector.