Food irradiation development in Japan. In Japan, the first food irradiation research was carried out on the preservation of fish and fishery products. In 1966, the Atomic Energy Commission of the Japanese Government (JAEC) decided the promote the National Project on Food Irradiation and, in 1967, the Steering Committee on food irradiation research in the Atomic Energy Bureau, S.cience and Technology Agency, selected the following food items as of economic importance to the country, i.e., potatoes, onions, rice, wheat, Vienna sausage, kamaboko (fish meat jelly products) and mandarin oranges. The National Project is expected to finish at the end of the 1981 fiscal year. Based on the studies by the National Project, irradiated potat,.oes were given "unconditional acceptance" for human consumption in 1972. Already in 1973, a potato irradiator was built at Shihoro, Hokkaido. In 1980, the Steering Committee submitted a final report on ,the effectiveness and wholesomeness studies on irradiated onions !,o the JAEC. This paper gives a brief explanation of the legal aspects of food irradiation in Japan, and the present status of wholesomeness studies on the seven items of irradiated food. In addition, topics concerning food irradiation research on kamaboko, especially on the effectiveness and" a' new detecting method for the irradiation treatment 'of these products, are outlined. Toshiharu Kawabata *Department of Biomedical Research on Food, National Institute of Health, Tokyo, Japan.