Descriptions are provided of chromosomal sets and comparative analyses of C-banded chromosomes of the spiny mice from the genusAcomysGeoffroy 1838, which were collected from five localities in Ethiopia (Gamo-Gofa province: Konso area, Arba Minch; upper part of Awash valley: Koka area; middle part of Awash valley: Awash National Park and 70 km North from Awash National Park). Two karyotypic forms were discovered: one, as expectedA. cahirinusDesmarest 1819 (2n= 36, NF = 68) and one new for the Ethiopian fauna 68-chromosomalAcomyssp. The distribution of these forms is discussed. Details of the C-banded chromosomes ofAcomys cahirinusandAcomyssp. are given for the first time. It was shown that both these karyotypes possess mainly pericentromeric heterochromatin and have insignificant differences in their quantities. It is possible that heterochromatin variations did not make a contribution to the karyotypic evolution ofAcomys.Apparently, chromosomal evolution in this genus was determined by Robertsonian or tandemic type translocations.