The Ecoregion’s forests are of world value and encompass 412 thousand km, 39% of the region’s total area (located predominantly in the areas of Russia and Kazakhstan). It contains some of the world's largest unbroken stretches of Siberian fir, pine and larch trees.
The dark coniferous taiga is particularly remarkable. It holds the world’s largest mountain cedar forestland (Siberian pine) which provides the habitat for relict nemoral (sylvatic) plant and lichen species.
The mountain areas of the region give life to 2 of 10 world’s largest rivers – the Ob and the Yenisei with total watershed of over 5.5 millions of square km. The ecoregion is also rich with lakes, they are over 27 thousands. The largest ones are Khuvsgul, Uvs and Teletskoe.
The Altai Sayan ecoregion is famous with its eternal snow-topped mountains which keep large fresh water reserves; glaceries of 49 cubic km. Big glaceries are located in the Central and Southern Altai, especially on the ranges of Katunsky, Taldurinsky, Ak-Turu, Munku-Sardyk, South and North Chuisky, Kryzin, and Mongol Altai.
Harsh continental climate and complex relief serve as determining factors for a wealth of flora. The list of plants includes over 600 species of mosses, 1200 lichens, over 3500 species of vascular plants. Of Altai-Sayan’s flora, 16% are rare or endangered and 9% are endemic species.
680 species of the vertebrates are registered in the Ecoregion. Among them: 77 species of fishes, 8 species of amphibians, 25 species of reptiles, 425 species of birds and 143 species of mammals.
39 species are endemic. For instance, Altai snowcock (Tetraogallus altaicus), sky larc (Alauda arvensis alticola), Siberian white-toothed shrew (Сrocidura sibirica), tuvinian beaver (Castor fiber tuvinicus), Gobi-Altai field-vole (Alticola barakschin), pigmy jerboa Kozlovi (Salpingotus kozlovi), Siberian ibex (Capra sibirica).