◆1958.4
 Foundation of “Institute for Nuclear Radiation Research”, Faculty of Medicine

◆1961.4
 Foundation of “Research Institute for Radiation Biology and Medicine” (RIRBM)
 Abolishment of Faculty of Medicine Institute for Nuclear Radiation Research
 Foundation of Department of Radiation Biology, Department of Pathology and Cancer Research, Department of Epidemiology and Social Medicine, and Department of Internal Medicine
 Foundation of Department of Internal Medicine for RIRBM in the University Hospital

◆1961.9
 Set up 50 beds in the University Hospital

◆1962.4
 Foundation of Department of Hematology, Department of Geneticopathology, Department of Biochemistry and Biophysics, Department of Surgery
 Foundation of Department of Surgery for RIRBM in the University Hospital

◆1963.2
 Completion of the primary construction of the RIRBM building

◆1964.3
 Completion of the secondary construction of the RIRBM building

◆1965.3
 Completion of the third construction of the RIRBM building

◆1965.4
 Increase of the number of beds from 50 to 90 in the University Hospital

◆1967.6
 Foundation of “Center for Medical Records and Biomedical Materials of A-bomb Victims and Survivors”

◆1969.3
 Completion of the building of Center for Medical Records and Biomedical Materials of A-bomb Victims and Survivors

◆1969.4
 Foundation of Department of Biometrics

◆1970.4
 Change of the name of Department of Pathology and Cancer Research to Department of Pathology
 Foundation of Department of Cancer Research

◆1971.3
 Completion of the fourth construction of the RIRBM building

◆1974.4
 Change of the name of Center for Medical Records and Biomedical Materials of A-bomb Victims and Survivors to “Data and Specimens Center of Atomic Bomb Disaster”

◆1983. 3
 Completion of Tritium Experiment Laboratory

◆1984.3
 Completion of Laboratory Animal Center for Radiation Research

◆1986.3
 Completion of building for RI Experiments (RI -A,B,C)

◆1994.6
 Change the name of Data and Specimens Center of Atomic Bomb Disaster to “International Radiation Information Center“
 Reorganization of 10 Departments into 4 major Divisions; Environmental Biology, Molecular Biology, Social Medicine and Clinical Research 

◆1998.6
 Foundation of “Radiation Research Center for Frontier Science”

◆2002.4
 Change of the name of Research Institute for Radiation Biology and Medicine (only Japanese)
 The 4 major Divisions were replaced by Division of Genome Biology, Division of Clinical and Experimental Oncology, Division of Radiation and Regeneration Control and Division of Bio-Medical Informatics including 15 departments and 2 departments by visiting professors
 Reorganization of International Radiation Information Center an attached research center

◆2004.4
 Hiroshima University was renamed Hiroshima University National University Corporation under the National University Corporation Law

◆2005.4
 Foundation of one department in Division of Bio-Medical Informatics

◆2008.3
 Completion of the RIRBM building reconstruction

◆2008.8
 Moved to the new building

◆2010.4
 Acknowledged as “Joint Usage / Research Center for Radiation Effects and Medical Science
 Reorganization of 4 major Divisions into 2 major divisions and 2 major centers; Division of Radiation Biology, Division of Radiation Bio-Medical Informatics, Research Center for Radiation Genome Medicine and Research Center for Radiation Casualty Medicine
 Reorganization of 16 research departments into 17
 Reorganization of International Radiation Information Center into “Division of Radiation Information Registry”
 Change of the name of Radiation Research Center for Frontier Science (only Japanese)

◆2016.4
 Establishment of “Network-type Joint Usage / Research Center for Radiation Disaster Medical Science” in FY2016 (2016-2021); Hiroshima University Research Institute for Radiation Biology and Medicine, Nagasaki University Atomic Bomb Disease Institute, and Fukushima Medical University Fukushima Global Medical Science Center

◆2021.1
 Completion of Experiment Building for Frontier Radiation Science

◆2022.4
 Ongoing project as “Network-type Joint Usage / Research Center for Radiation Disaster Medical Science” by 3 Universities; Hiroshima University Research Institute for Radiation Biology and Medicine, Nagasaki University Atomic Bomb Disease Institute, and Fukushima Medical University Fukushima Global Medical Science Center
 Reorganization of 2 major divisions and 2 major centers into 3 major divisions; Division of Radiation Basic Science, Division of Radiation Translational Medicine, and Division of Radiation Medical Science
 Reorganization of 17 research departments into 13
 Foundation of “Center for Radiation Disaster Medical Science”