In this study, we establish the seasonal variation of the Culpeo fox's diet in a seasonal ecosystem of south-central Chile. By scat analyses, 21 prey taxa were identified, 16 were animal and five were plant species. Mammals (88.47%) were the main biomass contribution with small seasonal fluctuations. Plants contributed the most to the differences observed in all seasons since they showed very marked changes. We determined that the Culpeo fox inhabiting the Andes of south-central Chile feeds mainly on small non-native mammals all year round, and supplements its diet opportunistically from items whose abundance oscillates seasonally.