Abstract. We have constructed phylogenetic trees based on sequence comparisons of mitochondrial NADH dehydrogenase subunit 5 gene for 11 Damaster blaptoides specimens from various localities of Japan. The specimens consist of eight ``subspecies. Coptolabrus fruhstorferi, Acoptolabrus gehinii, and Procrustes kolbei, which are taxonomically related to Damaster, have also been analyzed for comparison. Damaster is more related to Acoptolabrus than to Coptolabrus in the ND5 trees, in contrast to the generally accepted view that Damaster is derived from Coptolabrus, whereas Acoptolabrus is the sister group of Damaster/Coptolabrus. The emergence of Procrustes is much earlier than the rest of the genera. The Damaster subspecies are monophyletic. Four major lineages are recognized, which are geography linked within the Japanese archipelago. The origin and diversification process have been discussed based on these findings.