Abstract: This study was part of an expedition to the Altai Mountains in the Kosh Agach region of the Altai Republic, run by Biosphere Expeditions from 28 June to 7 August 2010. The aim was to continue a survey of snow leopard (Uncia uncia) in this area, as well as surveying the snow leopard's primary prey species, argali (Ovis ammon) and Siberian ibex (Capra sibirica), together with secondary prey species. Using the Snow Leopard Information Management System (SLIMS) developed by the International Snow Leopard Trust (ISLT), presence/absence surveys (SLIMS form 1) of snow leopard and prey species were conducted throughout the study period across the entire survey area. In 2010 surveys were extended to areas away from the Talduair massif site to valleys and surrounding ridges of the Karaghem mountain pass. Interviews with local, semi-nomadic herders also formed an important part of the research procedure. The expedition also collected data for extended mammal, bird and plant inventories. No signs of snow leopard presence were recorded this year and there was no indication that the areas had been visited and used since the 2009 expedition. The developing relationship between the predator and prey species seems to be very fragile, so perhaps the decline in the prey species (particularly argali) may have driven the snow leopard out of the area. In addition, human disturbance is considered to be a severe and growing threat and may be responsible for the declining mammal diversity in general. Yet the study area still retains its importance as a habitat for snow leopard and as a corridor for snow leopard dispersal. The survey area urgently needs protection, but involving the local community and raising public awareness is vital if conservation initiatives are to succeed. Work on establishing four additional nature parks in the Republic of Tuva and the Sailugem Nature Reserve in the Republic of Altai, which will protect the biggest Russian population of the snow leopard, is in progress.