New record of family of arhynchobdellida leeches (Orobdellidae) from Gageodo Island is presented. We have surveyed for land leeches in Korea from July to September in 2011 and found 1 species. This is Orobdella tsushimensis Nakano, 2011, reported for the first time in Korean Peninsula. This species gets the following characteristics: IV unianulate; 1/2+5 annuli between gonopores; bottle-shaped gastroporal duct; and epididymides in XVII–XIX. According to their morphological features, the diagnosis of O. tsushimensis is slightly emended. Phylogenetic analyses using mitochondrial COI, tRNACys, tRNAMet, 12SrDNA, tRNAVal and 16SrDNA markers show that the Orobdella specimen from Gageodo Isl. and O. tsushimensis from Tsushima Island, Japan, form a monophyletic clade and also confirm the identification of the Orobdella specimens from Gageodo Isl.