For the purpose of taxonomical description of marine oligotrich ciliates, water samples were collected from the southern coast of Korea (Masan Bay and Jangmok Bay). Ciliate cells were identified based on protargol impregnated specimens. As a result, four oligotrich ciliates were identified and redescribed: Rimostrombidium conicum (Kahl, 1932), Omegastrombidium kahli Song et al., 2009 and Spirotontonia turbinata (Song and Bradbury, 1998), and Spirotontonia grandis (Suzuki and Han, 2000). Of them, R. conicum, O. kahli, and S. turbinata are newly recorded and S. grandis is recorded for the second time in Korea, while the last one is redescribed to compare its variations according to locality. In addition, their abundances were analyzed and discussed the changes in accordance with water temperature and salinity.