In the massif of native old-growth spruce forests located at the junction of the Verkhnetoyemsky and Ustyansky districts of the Arkhangelsk Region, the species of plants, fungi and lichens listed in the Red Data Books of Russia (Calypso bulbosa, Lobaria pulmonaria and Sarcosoma globosum) or Arkhangelsk Region (Acolium karelicum, Arthonia vinosa, Chaenotheca gracillima, Corydalis solida, Poa remota, Pycnoporellus alboluteus, Ramalina thrausta) were found. The surveyed massif can be classified as a biologically valuable forest by both the structure of the tree stand and the presence and number of specialized and indicator species. Nowadays, native old-growth forests, both in the North-West of Russia and in Europe as a whole, are rare plant communities. Their preservation is important not only for the survival of species listed in the Red Books, but also for the preservation of the general biodiversity associated with the old-growth forests and ensuring the sustainability and restoration of natural forest communities. The creation of a specially protected natural area within the boundaries of the studied forest massif is recommended.