Feeding ecology of the critically endangered Asiatic cheetah was investigated from 2004 to 2009 in northeastern Iran where prey population has been depleted due to poaching. The survey was mainly based on scat analysis, complemented by kill monitoring and local inquiries of direct observations. Results of the research revealed that the Asiatic cheetahs mainly rely on medium-sized ungulates. However, with respect to low density of gazelles, they catch a considerable proportion of their food demands based on livestock which brings the cheetahs in direct conflict with local people. Meanwhile, smaller mammals only meet a small proportion of cheetah’s diet. Our data indicate high importance of enhancing conservation efforts in northeastern Iran as well as other cheetah habitats where normal prey ungulates have experienced severe decline.