Oxytricha multilineata, Mixophrya pantanalensis pantanalensis, and Caudiurostyla sinensis were isolated from soil samples collected from Cheongju-si and Yeoju-si, confirmed as new to South Korea. Oxytricha multilineata was distinguished from other congeners by seven dorsal kineties and dorsal bristles about 15 μm long. Mixophrya pantanalensis pantanalensis was characterized by five to seven lithosomes and six dorsal kineties. Caudiurostyla sinensis was characterized by colorless cortical granules present, 10-14 midventral pairs, 7-9 left and 6-9 right marginal rows and four or five dorsal kineties. We determined the ribosomal DNA sequences (including 18S rDNA, ITS1, 5.8S rDNA, ITS2, and partial 28S rDNA) from above three species. And the genetic distances were compared with their congeners.