The Dryopidae (Coleoptera) is composed of approximately 300 species worldwide belonging to 33 genera; however, members of the family have not been recorded in Korea. We collected and recorded adult specimens of Elmomorphus brevicornis Sharp (=E. brevicornis brevicornis Sharp) on piles of submerged twigs and branches of a decayed tree (Prunus sp.) from a mountain stream in southwestern Korea with a comparison of the type specimens of E. brevicornis amamiensis Nomura from Japan. Both of the subspecies are raised to the species level herein. Redescription, photographs, line drawings of diagnostic characteristics, distribution map, habitat, and taxonomic notes for Elmomorphus brevicornis are provided.