Abstract: The availability of wild prey is a critical predictor of carnivore density. However, few conservation pro- grammes have focused on the estimation and monitoring of wild ungulate populations and their trends, especially in the remote mountains of Central Asia. We conducted double-observer surveys to estimate the populations of ibex Capra sibirica and argali Ovis ammon in the mountain- ous regions of Tost Local Protected Area, South Gobi prov- ince, Mongolia, which is being considered for designation as a Nature Reserve. We also conducted demographic surveys of the more abundant ibex to examine their sex-ratio and the survival of young during –. The estimated ibex population remained stable in  and  and the es- timated argali population increased from  in  to  in . The biomass of wild ungulates was c. % that of live- stock. Mortality in young ibex appeared to increase after weaning, at the age of  months. We estimated the popula- tion of wild ungulates was sufficient to support – adult snow leopards Panthera uncia. The adult snow leopard population in our study area during –, estimated independently using camera-trap-based mark–recapture methods, was –. Based on our results we identify the Tost Local Protected Area as an important habitat for the conservation of these ungulates and their predator, the Endangered snow leopard, and recommend elevation of its status to a Nature Reserve.