Taxonomy of umbelliferous taxa Heracleum moellendorffii complex has been unclear in their species delimitation in the far-eastern Asian regions. In both Korea and China Heracleum moellendorffii was adopted for their description while H. sphondylium was chosen to describe Japanese Heracleum. From Genbank accessions, taxa collected from Kamtchatka and Promorskiy, Russia were defined as H. maximum, endemic taxon to North America. In this study, we reviewed the taxonomy of Heracleum moellendorffii complex in Korea and neighboring countries on the basis of molecular phylogenies derived from sequences of nuclear ribosomal DNA internal transcribed spacer (ITS) regions. From three Korean accessions of Heracleum investigated in this study, two types of ITS sequences were obtained; two accessions were related to Chinese H. moellendorffii var. moellendorffii and North American H. maximum without forming a clade while the other one was identical to accession from H. maximum from Primorskiy, Russia. In the other hand, Japanese H. moellendorffii (=H. sphondylium ssp. sphondylium var. nipponicum in the flora of Japan) was closely related to H. maximum accessions from Korea and Russia, not nested within the clade comprising several subspecies of H. sphondylium. In order to delimit species boundaries among putatively closely related Heracleum species in fareastern Asian countries, more samples and much more rapidly evolved DNA regions must be investigated with interpretation of morphological and anatomical features.