Abstract: The karyotype of the Tufted Deer (Elaphodus cephalophus) is first investigated with cultured fibrolasts from the lung and skin of two animals (one male and one female).The diploid number is 48,in the male and 47,in the female.G-band analysis shows that chromosomes 25 and 26 of the male just correspond to the long and short arms of chromosome 24 of the female,respectively.C-band observations shows that a pair of chromosome 23 and a chromosome 24 in the female and a chromosome 23,a chromosome 24 and a chromosome 25 in the male all contain rich heterochromatin.We think that these specific chromosomes probably relate to the sexual determination.The Ag-As technique reveals clearly silver stained spots at the secondary constrictions of two pairs of autosomes 1 and 2.In addition,the spontaneous frequencies of the sister chromatid exchanges (SCE) of this species are calculated.The average SCE number per cell is 6.2.