Taxonomic study of the genus Hemerocallis (Liliaceae) in Korea was conducted based on morphological data. H. middendorffii was distinguished from its related taxon H. dumortieri by the trait of coriaceous long bract with green color. H. taeanensis was distinguished from its related taxon H. minor by its odorless flowers, longer perianth tube and leaf length. H. thunbergii was distinguished from its related taxon H. lilioasphodelus by its long perianth tube. Lastly, H. hakuunensis was distinct from its related taxon H. hongdoensis as a result of its extreme branching of scape and short leaf width. From this study, it was revealed that H. minor, H. lilioasphodelus, and H. dumortieri were distributed only in the northern part of the Korean peninsular.