Abstract: The mammal fauna of Uzbekistan's mountain ecosystems is represented by some 60 species. Data on mammal species composition in the Western Tien Shan (48 species) and Pamir-Alai (57 species) is given. A quantity of species endemic to the mountainous ecosystems of Uzbekistan is defined. Quantities of nine rare species inhabiting the mountain ecosystems, including snow leopard, are given. Number of snow leopard in Pamir-Alai and the Western Tien Shan is estimated to be 30-50 animals.