Contracted services are an integral part of the design, construction and operation of a nuclear facility. Changes in the nuclear industry sector, including varied availability of nuclear expertise, the expansion of the international supply market and the introduction of new technologies, have tended to increase licensees’ use of contracted services. These changes have created challenges for licensees and regulators related to the retention of nuclear expertise, the effective management of the interfaces between the licensees and contractors, and the oversight of contractor manufacturing quality in the context of greater multinational diversity. The regulatory body must address these challenges to provide assurance that the licensees maintain their responsibility for the safety of the facilities, regardless of who provides goods and services or where the activities involved in the supply chain take place. This report is intended to assist regulatory bodies in assessing their current practices for the regulatory oversight of licensees’ use of contractors, and adapting them where necessary to meet the evolving situation.