In this paper, we present an analysis of the sex chromosomes of four hamster species after application of different staining techniques. The mitotic X chromosomes show a striking similarity in G-banding pattern but rather great differences in their C-banding patterns. A presumably homologous euchromatic segment that exhibits two distinct G-bands appears in the X chromosome of each species. The Y chromosome of Cricetus cricetus is in contrast to those of the other species, because it reveals a relatively well-differentiated G- and C-banding pattern. Inmeiotic metaphase I, interstitial chiasmata can be found in the sex bivalents ofCricetus cricetus and Cricetulus griseus, whereas the gonosomes of Mesocricetusauratus and Phodopus sungorus sungorus are terminally associated. The regionsthat are involved in pairing or association are always heterochromatic.