DNA polymorphisms in the psi beta 1-beta-globin gene region in nine Asian macaques (Macaca fuscata, M. mulatta, M. nemestrina, M. cyclopis, M. fascicularis, M. arctoides, M. radiata, M. maura, and M. assamensis) were examined using several restriction endonucleasese and the human psi beta 1, delta IVS2, and beta IVS2 probes. The BamHI site 3' to the beta-globin gene was polymorphic in M. fuscata and M. mulatta, while the HincII site and the EcoRI site in the psi beta 1-globin gene region was highly polymorphic in M. fuscata and M. mulatta, respectively. These polymorphic sites also seem to be present in other Asian macaques. The present study of the polymorphism at the BamHI site 3' to the beta-globin gene in Asian macaques supports, at the nuclear DNA level, the idea that the fascicularis group including M. fuscata, M. mulatta, M. cyclopis, and M. fascicularis is different from other Asian macaque groups.