The ostracod assemblages of the Baksian and Dolborian horizons of the Chunya River basin (a right tributary of the Podkamennaya Tunguska River) have been studied. They add essentially the paleontological characteristics of Upper Ordovician deposits of the Siberian Platform. The age of deposits was verified and the studied sections were correlated with the Gaindinskaya 3 reference borehole. Two new genera and 9 new species were described. Images for known ostracod species are given.