The rosters collected loom various keshwater habitats, such as rivers, steams, lakes, ponds, and rice paddies at twenty-four different sites in Korea were investigated. Eleven species and/or subspecies in three families of monogonont freshwater rotifers were identified, of which two species, Notholco marina and Lecane (Monostyra) stenroosi stenroosi were new to Korea. A key is presented for the twenty-two Korean species and/or subspecies which have been described by the previous taxonomic reports and the present study.