Radiobiology assesses the biological hazards of exposure to radioactive substances and nuclear radiation. This article explores the history of radiobiology in twentieth-century China by examining the overlapping of radium research and biophysics, from roughly the 1920s Nationalist period to the 1960s Communist period; from the foreign purchase of radium by the Rockefeller Foundation’s China Medical Board during the Republican era, to the institutional establishment of radiobiology as a subset of biophysics in the People’s Republic. Western historiography of radiobiology highlights the (...) connection between the military development of nuclear weapons and the civilian use of radiation in biology, as well as the international export of radioisotopes and nuclear reactors. Considering the exclusion of China from Western atomic diplomacy, I argue that the study of the Chinese history of bomb-making and radiobiology is necessary not just to fill an existing knowledge gap, but more importantly to elucidate the influence of the Chinese nuclear weapons program and Cold War atomic politics on Chinese life-science enterprises. Through examining the formational history of the radiobiology program in China, I hope to shed light on the implications of the atomic age for Chinese biology in the twentieth century. (shrink)