Abstract: Members of the subfamily Ischyromyinae, the most derived of the Paleogene rodent family Ischyromyidae, have previously been reported only from North America, where they are relatively abundant in deposits ranging in age from late Middle Eocene through Middle Oligocene. The two lower jaws from North China described here are the first record of the subfamily in Asia. This discovery both provides another example of faunal exchange between Asia and North America during the Middle Eocene and assists us in determining the age of the Changxindian Formation.