We investigated butterfly species diversity on nineteen uninhabited islands around Imja-myeon, Shinan-gun, Jeonnam, Korea. A total of 14 species belong to 5 families were identified. Species of Papilionidae were the most abundant with 5 species, followed by Lycaenidae (4 species). A Lycaenid butterfly, Pseudozizeeria maha (Kollar), was the most dominant species on the surveyed islands. The total number of species was the highest at island Daenorokdo (6 species). To investigate the factors that determine butterfly diversity, we analyzed the relationships between number of species and island area, distance from the largest island nearby, and maximum elevation. We found that island area (R2=0.413, p=0.003) was significantly correlated with butterfly diversity, but other variables such as distance from the largest island nearby and maximum elevation were not correlated.