The known Korean sertularian hydroid fauna consists of 41 species(including Sertularella areyi reported by Rho, 1974) of 10 genera in two subfamilies. Of which 20 species have been previously known and the following 21 species are newly recorded in Korean waters (Dynamena cornicina, Sertularella distans. Sertularella tongensis, Sertularella obtusa, Sertularella tenella, Sertularella pedrensis, Sertularella gayi, Abietinaria traski, Sertularia desmoides, Sertularia turbinata, Thuiaria suensoni, Thuiaria plumosa. Thuiaria thuia, Thuiaria nuttingi, Thuiaria similis, Thuiaria articulata, Thuiaria carica, Selaginopsis triserialis, Selaginopsis cornigera, Selaginopsis trilateralis and Selagiopsis pinnata). They were sampled from the depths below 100m. Of 41 species Sertularellla miurensis is the most common species and 10 species, Dynamena cornicina, Sertularella distans, Sertularella lagenoides, Sertularella areyi, Sertularella pedrensis, Sertularella gayi, Sertularia hattorii, Sertularia turbinata, Thuiaria plumosa and Thuiaria articulata are scarcesly founded in Korean waters. 25 out of 41 species are shared with Japan and the remaining 16 species so far have been unknown from Japan. The coastal waters of Korea are divided into three regions, the East Sea, the South Sea and the Yellow Sea, on the basis of the geographical distribution and the community coefficient. Concerning the distribution in each region, 11 species occur in the East Sea, 39 species in the South Sea and 23 species in the Yellow Sea The community coefficient between the South Sea and Yellow Sea(0.733) is higher than those of the South Sea-the East Sea (0.476) and the East Sea-the Yellow Sea(0.438).