As a result of the faunistic study on the subterranean cyclopoid copepods, four species of three genera in the family Cyclopidae are reported from nine limestone caves and a lava tube in South Korea: Megacyclops magnus (Marsh, 1920), Acanthocyclops orientalis Borutzky, 1966, A, robustus (Sars, 1863) and Diacyclops suoensis Ito, 1956, all of them new to Korean fauna. This paper deals with the taxonomic accounts and illustrations of the four species with the redescription of A. orientalis. This is the first taxonomic study on the cave-dwelling cyclopoid copepods from Korea.