The diversity of Palaearctic chipmunks was analysed using a set of morphological (705 skulls from entire range) and genetic features (144 specimens, cytochrome b gene). Based on the results, we propose three taxa within Eutamias sibiricus. These are E. s. sibiricus, inhabiting Russia, the extreme northeast of the Korea Peninsula, Mongolia, Hokkaido Island, and northeast China; E. s. barberi, inhabiting the Korea Peninsula except for the extreme northeast region, and E. s. senescens, inhabiting central China.