The genus Hypena Schrank is a large but poorly-defined taxon. Hypena nakajimai Kishida, which is reported here for the first time in Korea, highlights the Hypena's current taxonomic situation — a lack of phylogenetic analysis, taxonomic revision and numerous tropical species descriptions. H. nakajimai was initially found by Sugi more than 40 years ago, but the species was officially named by Kishida in 2010. It is expected that numerous undescribed and unknown Hypena species still remain to be discovered.The present study reports the thirtieth Korean Hypena species, provides its diagnosis, re-describes its habitus and male genitalia and emphasises the importance of describing Hypena and its difficulties.