Sequences of mitochondrial DNA (mtDNA) cytochrome b gene (1,140 bp) and control region (803 bp) of Siberian flying squirrels from Korea (Pteromys volans aluco) and Mt. Changbai of northeast China (P. v. arsenjevi) were obtained to reexamine the taxonomic status of the Korean subspecies. In the cytochrome b gene, six haplotypes of P. v. aluco formed a clade with six haplotypes of P. v. arsenjevi, and in control region, seven haplotypes of P. v. aluco formed a clade with six haplotypes of P. v. arsenjevi. Furthermore, six haplotypes of cytochrome b gene of P. v. aluco from this study formed a clade with four haplotypes of P. v. arsenjevi in far-east Russia obtained from GenBank. We also investigated the research papers previously published that reported the length of tail vertebrae of P. volans, and found that the length was not sufficiently large as to be a key character of P. v. aluco. This result is not consistent with morphological description for its haplotype. Therefore, we conclude that P. v. aluco from Korea might possibly be a synonym of P. v. arsenjevi from northeast China and nearby Russia.