The common mole rat, Tachyoryctes splendens, belongs to family Rhizomyidae or Muridaern(Mammalia; Rodentia). Somatic chromosomes of the species were studied from 9 localities inrnEthiopia (Mugo, Masha, Bure, Ziway, Asebe Teferi, Alemaya, Entoto, Sebeta and Debre Sina)rnusing the standard Giemsa staining and C-banding techniques. Six different karyotypic formsrnwere found. These variations were revealed as differences in chromosome morphology,rnautosomal fundamental number, amount and distribution of heterochromatin. However, there wasrnno variation in diploid chromosome number and specimens from all the localities had 2n=48. Thernsix karyotypic forms had the following karyotypic formulae: Mugo, Masha and Bure (12m + 10strn+ 26a), Debre Sina (10m + 8st + 30a), Ziway (8m + 12st + 28a), Asebe Teferi (8m + 4st + 36a),rnAlemaya (8m + 6st + 34a), and Entoto and Sebeta (7m + 1 sm + 2st + 38a). C-banding revealedrnthat, in addition to the Y-chromosome (except in Entoto), 12, 12, 36, 4, 6, 4, 4 autosomes inrnMugo, Masha, Ziway, Asebe Teferi, Alemaya, Entoto and Sebeta were C-positives, respectively.rnThe telomeric region of the long arm of the X-chromosome was also C-positive in animals fromrnEntoto and Sebeta. The present study did not confirm the earlier suggestions that the number ofrnbiarmed chromosomes of T. splendens decreases with the increase in aridity and the number ofrnheterochromatic arms may exhibit an altitude gradient. We recommend further studies like Gbanding,rnzoogeographical, physiological and hybridization studies on T. splendens from differentrnparts of the distribution range of the species so that the results could supply information to revealrnfactors associated with the existing variations, and to draw a valid conclusion that could be usedrnin clearing the taxonomic uncertainties in this animal.rnKey words/ Phrases: Tachyoryctes splendens, chromosome, karyotype, C-banding, Ethiopia