To reappraise the taxonomic status of two Korean endemic plants, Eranthis byunsanensis and Eranthis pungdoensis, we analyzed five taxa of that genus plus three out-group genera (Cimicifuga, Anemonopsis, and Anemone). In all, 52 representative accessions were examined for nrDNA (ITS) and 43 accessions for cpDNA (trnH-psbA, rps16, trnL, and trnLF). In the ITS region, all of the aligned sequences from E. byunsanensis had the same ribotype as from E. pungdoensis. For the ITS phylogeny, E. pungdoensis could not be distinguished from E. byunsanensis. However, the clade of E. byunsanensis, including E. pungdoensis, was separated from Eranthis pinnatifida of Japan, which has a distinct ribotype and forms a sister group. In our cpDNA analysis, E. byunsanensis showed paraphyly, and the clade of E. pungdoensis was nested within the E. byunsanensis clade. Haplotypes of each population of E. byunsanensis were highly variable, and TCS analysis of that species implied that the Jeju population is ancestral. Moreover, the cp-group of E. pungdoensis was separated from the other cp-groups by five substitutions and five indels. Therefore, based on these DNA data and TCS analysis, we advise that the taxonomic status of E. pungdoensis be treated as E. byunsanensis B. Sun var. pungdoensis (B.U. Oh) S.H. Yeau, C.S. Lee & N.S. Lee, stat. nov.