The collection of fossil Rodentia from the Miocene Tagay fauna comprises Aplodontidae, Mylagaulidae, Sciuridae, Gliridae, Castoridae, Eomyidae and Cricetodontinae. Represented by three taxa the Cricetodontinae dominate the rodent assemblage of the Tagay fauna. The fossils were collected by wet-screening of test samples along the section Tagay-1 at Tagay Bay of Olkhon Island. Here, we report on the medium-sized Democricetodon cf. lindsayi, the very small Democricetodon sp. and the large Gobicricetodon filippovi. The primitive dental pattern of D. cf. lindsayi and G. filippovi suggest archaic members of the genera, and an age around the Early/Middle Miocene transition.