Karyotypes of four Chinese species of field miceof the genus Apodemus were examined, includingApodemus chevrieri (diploid chromosome number,2n=48, fundamental number of autosomal arms,FNa=56), A. draco (2n=48, FNa=48), A. ilex(2n=48, FNa=48), and A. latronum (2n=48, FNa=48).Karyotypes of A. chevrieri, A. draco, and A. ilexare reported here for the first time, providing usefulinformation for their species taxonomy. Determiningthe karyotypes of all species of Apodemus in Asia,both in this and previous studies, provides a solidoverview of the chromosome evolution and speciesdifferentiation of the genus in East Asia. In additionto allopatric speciation, chromosome rearrangementslikely played an important role in the formation of thefour Apodemus species groups as well as speciationwithin each group in East Asia. For example, increasedcentromeric heterochromatin in A. latronum may havecontributed to the post-mating reproductive isolationfrom the A. draco-A. ilex-A. semotus clade.