From an evolutionary point of view, endozoochory can be considered as a mutualistic process, in which both the plant seed- dispersing animal species and the dispersed plant species benefit. Disperser benefits may be direct, by using the dispersed plant species as a food source, and indirect, by promoting the distribution of these food plants. Despite biomass loss involved, plant species may benefit from endozoochory, because it promotes long-distance dispersal and linked advantages. We tested this mutualism hypothesis in the Poľana Biosphere Reserve, central Slovakia, with red deer (Cervus elaphus) as disperser. We collected data on distances covered by red deer between seed ingestion and excretion sites, and the corresponding vegetation by VHF telemetry and GIS analysis. We assessed the viable seed content of red deer dung by a germination test. Information on forage palatability, habitat and seed longevity of the dispersed species were taken from literature. From a total of 400 g dry red deer feces, 1766 seedlings emerged, belonging to 43 species. Most of the observed dispersal distances exceeded 100 m, which is commonly considered as a minimum for long-distance dispersal. Red deer transported mostly seeds from a variety of vegetation types to forests. Our results support the hypothesis that endozoochory is a mutualistic process. We conclude that, since landscapes are changing due to global warming and land use changes, it is important for the maintenance of plant species diversity to promote migration and free ranging of large grazers like red deer, by means of infrastructural measures.