Abstract: Snow leopard ecology, distribution and abundance in Mongolia were studied between 1993 and 1999. I placed VHF and satellite radio-collars on 4 snow leopards, 2 males and 2 females, to determine home ranges, habitat use, movements, and activity. Home ranges of snow leopards in Mongolia were substantially larger than reported elsewhere. Males ranged over 61 – 142 km2 and female 58 to 1,590 km2. Cats had crepuscular activity patterns with daily movements averaging 5.1 km. Intraspecific distances averaged 1.3 km for males to 7.8 km for males. Leopards selected moderately to very-broken habitat with slopes > 20o, in areas containing ibex. Leopard distribution and abundance was determined using sign surveys. Leopard range in Mongolia is approximately 103,000 km2 but cats are not uniformly distributed within that range. High-density areas include the eastern and central Transaltai Gobi and the northern Altai ranges. Relative leopard densities compared well with relative ibex densities on a regional basis. A snow leopard conservation plan was drafted for Mongolia that identifies problems and threats, and provides an action plan. Wild Bactrian camels occur in the Great Gobi National Park (GGNP) and are thought to be declining due to low recruitment. I surveyed camels by jeep and at oases, observing 142 (4.2% young) and 183 (5.3% young) in 1997 and 1998. Current range was estimated at 33,300 km2. Some winter and calving ranges were recently abandoned. Track sizes and tooth ages from skulls were used to assess demographics. A deterministic model was produced that predicts camel extinction within 25 to 50 years under current recruitment rates and population estimates. Gobi brown bears are endemic to Mongolia and may number less than 35. Three population isolates may occur. I collected genetic material from bears at oases using hair traps. Microsatellite analyses of nuclear DNA determined sixteen unique genotypes, only two of which occurred at more than one oases. Genetic diversity was very low with expected heterozygosity = 0.32, and alleles per locus = 2.3. Mitochondrial DNA sequences were compared to other clades of brown bear and found to fall outside of all known lineages.