Abstract: Four lagomorphs , Gobiolagus major, Hypsimylusyihesubuensis sp. nov. , Desmatolagus cf. D. vetustus ,and Desmatolagus sp. from a new late Eocene locality, Yihesubu, Nei Mongol, are described. Upper dental morphology of Gobiolagus major is known for the first time. Hypsimylus yihesu buensis sp. nov. helps to demonstrate this genus a lagomorph , not a eurymylid. The taxonomic position of D. vetustus , the most primitive species of Desmatolagus, is reconsidered.