Abstract: Home ranges for five radio-tagged snow leopards (Uncia uncia) inhabiting prime habitat in Nepal Himalaya varied in size from 11-37 km2. These solitary felids were crepuscular in activity, and although highly mobile, nearly 90% of all consecutive day movements involved a straight line distance of 2km or less. No seasonal difference in daily movement or home range boundry was detected. While home ranges overlapped substancially, use of common core spaces was temporally seperated, with tagged animals being located 1.9 km or more apart during the smae day. Spatial analysis indicated that 47-55% of use occured within only 6-15% of total home area. The snow leopards shared a common core use area, which was located at a major stream confuence in an area where topography, habitat and prey abundance appeared to be more favorable. A young female used her core area least, a female with two cubs to the greatest extent. the core area was marked significantly more with scrapes, Faeces and other sighn than non-core sites, suggesting that social marking plays an important role in spacing individuals. Snow leopards showed a strong preference for bedding in steep, rocky or broken terrain, on or close to a natural vegetation or landform edge. linear landform features, such as a cliff or major ridgeline, were preferred for travelling and day time resting. This behavior would tend to place a snow leopard close to its preferred prey, blue sheep (Psuedois nayaur), which uses the same habitat at night. Marking was concetrated along commonly travelled routes, particularly river bluffs, cliff ledges and well defined ridgelines bordering stream confluences--features that were most abundant within the core area. Such marking may facilitate mutual avoidance, help maintain the species' solitary social structure, and also enable a relatively high density of snow leopard, especially within high-quality habitat.