Former RERF Chairman Dr. Shigenobu Nagataki passed away on Saturday, November 12, 2016, at the age of 84. At the time of his death, Dr. Nagataki served as President of the Radiation Effects Association and Professor Emeritus of Nagasaki University. He graduated from the University of Tokyo, where he obtained his M.D. and Ph.D. degrees. Dr. Nagataki made it his life’s work to conduct radiation-induced thyroid cancer studies, such as thyroid cancer research of atomic bomb survivors and childhood thyroid cancer caused by radioactive iodine from the April 1986 Chernobyl nuclear accident. In particular, following his retirement from Nagasaki University, he participated in international efforts (WHO, IAEA, EU, etc.) that aimed to study the health consequences of the Chernobyl disaster. In his role as RERF Chairman, from July 1, 1997, to June 30, 2001, Dr. Nagataki not only focused on management of the two laboratories, but also on promotion of basic science into thyroid cancer among young A-bomb survivors and on training of young researchers. Following the March 2011 Fukushima Daiichi nuclear power plant accident, he chaired several government committees that aimed at recovery of the local community, as well as led active discussions on thyroid cancer at the “5th International Expert Symposium in Fukushima on Radiation and Health,” held at the end of September 2016. For many reasons, Dr. Nagataki’s sudden death is a profound loss.