The brown bear (Ursus arctos L., 1758) is a widespread bear species inhabiting the forest zone of Eurasia, including the Republic of Yakutia. The association with forest habitats explains why the Pleistocene findings of U. arctos fossils are rare in the northern part of Eastern Siberia, where open steppe-tundra and steppefied landscapes prevailed during the Pleistocene. Fossils of U. arctos that have been found on the territory of Yakutia are dated since the beginning of the Middle Pleistocene. These are mainly the skulls and bones of the postcranial skeleton. In the present study, using comparative morphological analysis, computed tomography, and DNA sequencing, we describe a first mummified carcass of a brown bear individual that inhabited the New Siberian Islands (Northeast Siberia) in the Middle Holocene, approximately 3,500 years BP, which was found in the permafrost of Bolshoy Lyakhovsky Island, Russia, in 2020.