Abstract:  New cricetids (Pappocricetodon neimongolensis sp. nov., Pappocricetodon cf. P.zhongtiaensis, Pappocricetodon sp.) are reported from the basal strata of the Irdin Manha Formation in the Huheboerhe section in Nei Mongol, China. P. neimongolensis is characterized by the following features: presence of a P4 or DP4; anterocone small; anterior arm of protocone on M1 well-developed and connected to anterocone; distinct paraloph joining protoconule and paracone; protocone on M1 lacking posterior arm; posterior arm of protocone present on M2; hypocone of M3 prominent; protoconid generally positioned anterior to metaconid on m1; posterior arm of protoconid on m2 complete; m3 unreduced, with “S”-shaped ectolophid. P. neimongolensis is morphologically similar to the early cricetid Pappocricetodon antiquus. Pappocricetodon sp. has a prominent anterior lobe, andPappocricetodon cf. P. zhongtiaensis has a distinct mesoloph. These fossils suggest that cricetids were already diversified in the Middle Eocene, and probably originated earlier than the Irdinmanhan.