Phytophagous insects were surveyed from field populations of Compositae weeds in the order Campanulales. Forty five insect species including unidentified ones of 43 genera in 5 orders and 17 families were recorded from 16 species in 12 genera of Compositae weeds. The hemipterans and coleopterans were the most abundant insects representing 13 and 13 species, repectively. Aphids and leaf beetles were important phytophagous insects on Compositae weeds. The potential biological control insects were Uromelan gobonis and Aethes cnicana on Cirsium japonicum var. ussuriensis and Cryptosiphum artemisiae on Artemisia lavandulaefolia. The leaf beetles, Chrysolina aurichalcea, Longitarsus succineus, Basilepta fulvipes, and Hamushia konishii were often collected from A. lavandulaefolia. Aphids and leaf beetles showed host specificities. The roles of hemipterans collected from the flowers of A. lavandulaefolia and Erigeron canadensis were questionable.