Eupiestus rotundifrons Park and Ahn, new species is described from Korea. Adults of the new species were collected under bark and are similar to those of Eupiestus sikkimi Fauvel from China in having a subtriangular head with a curved anterior margin and slightly transverse antennomeres 6–10. However, the new species can be distinguished from E. sikkimi by the slightly constricted superior marginal lines of the pronotum, the slightly concave dorsolateral ridges of the elytra, and the different form and structure of the aedeagus. A description and illustrations of the habitus and diagnostic characters of the new species are provided.