Analysis of prey remains in scats, particularly hairs, is widely used to study diet of mammalian predators, but identification of hair is often difficult because hair structures vary considerably both within and between species. Use of photographic reference of diagnostically important hair structures from mammals occurring in a predator's habitat has been found to he convenient for routine identification. A photographic reference key was developed for the identification of hairs of the mammals known to occur in a snow leopard (Panthera uncia) habit at in the Annapurna Conservation Area, Nepal. The key included a photographic reference of the diagnostic hair structures of nine species of wild and five species of domestic mammals. The cross-sectional appearance, shape and arrangement of medulla, the ratio of cortex to medulla. and the form and distribution of pigment in medulla and cortex were important diagnostic aids in the identification of hairs.