The puma (Puma concolor) is widely distributed in the alpine highlands of the Andes, but its diet has rarely been described in ecosystems above 4300 m. We collected and examined 21 puma scats from the Salinas y Aguada Blanca National Reserve (RNSAB) between 2013 and 2015. We identified 10 species of prey, in addition to unidentified birds and small rodents. Small and medium animals were the most frequent prey, although wild camelids contributed the greatest proportion of biomass. We also recorded the presence of mesopredators and domestic dogs in puma scats. Our results suggest that the puma could play a key role in the configuration of trophic networks in the RNSAB, and that this can contribute considerably to the ecosystem balance.