[en] Assess, research, protect, anticipate and share: these are the missions of IRSN in the service of public authorities and the public. IRSN's uniqueness lies in its ability to bring together researchers and experts to anticipate questions regarding the evolution and control of nuclear and radiological risks. The women and men of IRSN are committed to publicizing their work and sharing their knowledge with society. They thus contribute to improving access to information and creating the conditions for dialogue with stakeholders. IRSN participates in formulating government policies on nuclear safety and security, health, the environment and emergency response management. A French industrial and commercial public undertaking (EPIC) under the joint responsibility of the Minister for the Environment, the Minister of Defense, and the Ministers for Energy, Research and Health, IRSN fully follows governmental modernization policies as evidenced by its approach to risk management and the implementation of a comprehensive policy on social responsibility. This annual report presents IRSN's Highlights and Key figures of the year 2020, as well as its actions in the domains of: Research, Nuclear safety expertise, Nuclear defense safety, nuclear security, nuclear and chemical non-proliferation, Radiation protection of people and of the environment. The institute's transformation, corporate social responsibility, Organisation chart and Governing bodies are reported too. A financial report is attached to the French version of the report