The International Commission on Radiological Protection (ICRP) is a community of more than 250 globally-recognised experts in radiological protection science, policy, and practice from more than 30 countries, and is also a charity. The objective of the system of radiological protection is to provide an appropriate level of protection for people and the environment against the harmful effects of radiation exposure without unduly limiting the individual or societal benefits of activities involving radiation. This article briefly overviews the history of ICRP, the development of the system of radiological protection, and the recent trends of its publications, especially from the viewpoint of medicine.