The beetle family Ciidae, represented by Octotemnus laminifrons Motschulsky, 1860 and Octotemnus japonicus Miyatake, 1954 is presented for the first time in Korea. The beetle family Ciidae Leach is a relatively moderate family, which comprises about 640 described species in 42 genera worldwide. This family is distributed throughout the world. Ciids are minute fungus-feeding beetles, which are associated with the mycelia and fruiting bodies of wood-rotting fungi. These beetles are considered mycetobiont because they depend upon the basidiocarps for food and breeding throughout their life span. And also ciids are important components of the saproxylic fauna of many forests ecosystems and a number of species are considered rare or threatened and are associated with old growth forests or undisturbed forest conditions. A habitus photographs of adults, description, illustrations of diagnostic characters, and host fungi are provided.