A survey of the insect fauna of Gadeok-do Island, an island near the port city of Busan, Korea and an important quarantine site, was conducted from March to September of 2011. Specimens were collected using a sweep net and a malaise trap. Eight orders, 80 families, and 205 species of insects were recorded from Gadeok-do Island. Among them, 54 species were collected from the malaise trap. All species collected during the study were included in the Checklist of Korean Insects and there were no species newly reported from Gadeok-do Island. Two species were recognized as being endemic to Korea as designated by the Ministry of Environment. A species list and photographs of some of the species collected in Gadeok-do Island is provided.