A good-preserved fusulinid fauna is reported for the first time from Kosado Hill, Sado Island in central Japan. The fusulinids were found in erratic conglomeratic limestone blocks that are left alone along the forestry road. The fusulinid fauna is characterised by abundant occurrence of the genus Lepidolina including Lepidolina kumaensis, L. gigantea and L. multiseptata. The species of the genera Chusenella, Kahlerina, Pseudokahlerina, Reichelina, Rauserella and Nankinella have also been found in the fauna. The fusulinid fauna of Kosado Hill can be correlated to that of the Kuma Formation of central Kyushu, indicating Midian of the Middle Permian. The present limestone is identical in age with radiolaria-bearing black mudstone cropping out at southeast of the fusulinid locality. Based on the fusulinid faunal composition, the present limestone should be geotectonically ascribed to the Maizuru and/or Kurosegawa Terranes of Southwest Japan. The radiolaian fauna of Kosado Hill, however, shows similaritiy to that of the Ultra-Tanba and/or Kurosegawa Terranes. In terms of both fusulinid and radiolarian faunal characteristics, it is concluded that the Permian strata of Kosado Hill can be correlated to those of a series of Palaeozoic terranes such as the Maizuru, Ultra-Tanba and Kurosegawa Terranes.