A total of 52 gall-inducing species of Cecidomyiidae (Diptera) (53 in the sorts of midge gall, because one poluphagous species was included) were recognized to occur in the Korean Peninsula (including surrounding islands) through literature survey, field surveys by Dr. K. Yamagishi and ourselves, and by examining photographs of arthropod galls talen by the late Prof. W. -H. Paik and one of us, JCP. The previous and current identification of these Korean gall midges relied largely upon their gall morph and host plant species that correspond to those of Japanese gall modges. The identification of these gall midges was considered to be mostly reliable, because DNA analysis suggested that some South Korean gall midges were indentical with Japanese gall midges when thwy induce the same sorts of gall on the same host plants as those in Japan. At the moment, 47 (88.7%) out of the 53 sorts of Korean midge galls were common to Japan. This means that more numerous midge galls will be detected in the Korean Oeninsula on the plant species or genera that have been known as host plants of the Japanese gall midges.