The first checklist of the Marsh Beetles (Coleoptera: Scirtidae) is presented based on literature records and specimens collected from Korean peninsula. The total of 19 species belonging to seven genera were catalogued. All recorded genus Cyphon species from Korean peninsula are transferred to genus Contacyphon by Zwick et al., 2013: Contacyphon coreanicus Klausnitzer, 1975, C. consobrinus Nyholm, 1949, C. laevipennis, C. padi (Linnaeus, 1758), C. palustris Thomson, 1855. Of these C. padi (Linnaeus), Hydrocyphon nakanei Yoshitomi, 2001, H. satoi Yoshitomi, 2001, Odeles inornata (Lewis, 1895), and Scirtes sobrinus Lewis, 1895 are recorded for the first time in South Korea. Photographs of dorsal adults and line drawings of diagnostic characters of new recorded Scirtids are provided. This work was supported by a grant from the National Institute of Biological Resources (NIBR), funded by the Ministry of Environment (MOE) of the Republic of Korea (NIBR201801201).