The taxonomic revision of the flounders of the suborder Pleuronectoidei was made based on the specimens collected from the coasts of the Korean Peninsula from 1989 to 1993. The flounders of Korea are composed 34 species belonging to 24 genera and 4 families, and the keys to species, genera and families are provided with redescriptions and distributions. Three species of the flounders are found to be new to Korea : Tarphops oligolepis (Bleeker) of the family Paralichthyidae, Parabothus kiensis (Tanaka) of the family Bothidae and Pleuronectes pallasii Steindachner of the family Pleuronectidae. Laeops lanceolata, previously recorded in the Korean fish list, was found to be synonym of L. kitaharai. The fishes of the families Paralichthyidae and Bothidae were distributed in the Yellow Sea and the southern coast of Korea, while most of the flounder species of the family Pleuronectidae except Limanda yokohamae, Eopsetta grigorjewi, and Pleuronichthys cornutus were found along the eastern coast of Korea. It appears that Korean flounders are similar to those of Chinese and Japanese faunas which include tropical and temperate species without endemics.