Specimens of nudibranchs have been surveyed by scuba diving from 9 localities along the Korean coast. By examination of morphological characteristics, four species in the superfamily Doridoidea which are new to Korea were identified, and re-described: Thorunna florens (Baba, 1949), Diaulula sandiegensis (Cooper, 1863), Jorunna parva (Baba, 1938), and Doris odhneri (MacFarland, 1966). In addition, radulae of three species were observed and photographed by using scanning electron microscopy. As a result of the study, 16 species of doridoidean nudibranch are now known from Korean waters.