This study details for the first time the food habits of the culpeo or Andean fox (Lycalopex culpaeus) in high areas of the Ecuadorian Andes during a complete annual cycle. Our objective was to identify prey species, calculate their contribution to diet and test for temporal variation. In total, 304 Andean fox scats were collected within the Podocarpus National Park (Loja province, southern Ecuador). By analysing the content of scats 413 prey items were identified and classified into eight prey groups. Subsequently, the frequency of occurrence (FO) for each prey group was calculated per month together with the relative contribution of estimated consumed biomass (CB). In addition, the Shannon-Wiener’s index was calculated as a measurement of monthly diet diversity. The results show a diet dominated by cervids belonging to the Mazama and Pudu genus (70% FO), followed by small mammals (30% FO), large rodents (12% FO), carnivorous species (10% FO) and lagomorphs (8% FO). There was temporal variation in the consumption of both deer and small mammals. Cervids also provided the major part of the consumed biomass (70% CB), the remaining prey categories each accounted for less than 11% CB. Negative correlations in consumption were observed between cervids and two other groups, rabbits and small mammals. Trophic diversity values fluctuated throughout the year showing a mean of 1.7. The results obtained show a diets very different from those previously reported; deer being the bulk of the diet instead of rodents or other mammals. The consumption of carnivorous species in the area was also high in comparison with other regions. Overall, this study clearly demonstrates that the culpeo is an important top predator in the high-Andean ecosystem.