This publication explains the concepts of quality assurance and quality control. It provides examples, illustrated by good practices, of their implementation within the processes of the management systems of nuclear facilities and describes how they are managed through interfaces with suppliers and subcontractors. The publication discusses the elements of a management system relevant for the quality assurance and quality control functions, such as the generation and retention of documented information. The information presented will help in ensuring the safe and economic operation of nuclear facilities and provide a neutral technical basis for dialogue between government bodies, regulators, plant operators and suppliers when dealing with management system, quality assurance and quality control issues.