Abstract: The distribution of nucleolus organizer regions in chromosomes of eleven primates were investigated by the silver-staining technique.Tupaia belangeri chinensis NORs were located on chromosomes 28 ph,29 ph and 30 ph.The NORs of five Macaca species (M.assamensis,M.nemestrina,M.speciosa,M.mulatta and M.cyclopis) were located on chromosomes 20 ph.In the Rhinopithecus roxellanae and Presbytis francoisi,P.phayei and Hylobates lar,their NORs were located on chromosomes 21 ph.The gibbon,Hylobates concolors on chromosomes 23 ph and 24 ph.NORs in all species studied were confined to different kinds of the marker chromosomes with secondary constriction.Finally,nucleolus organizer regions in chromosomes of these genera and species have been compared with each other.By comparison we can see that the species with the same or similar karyotype have the identical Ag-NORs and their evolutionary relationship are closer.