Carnivore diet studies insight on the health of the forest. The diet and prey preference of tigers of Parsa National Park (PNP) was studied from Nov-2019 to Feb-2020. The ratio of scat sample analyzed per tiger was 3.5 scats per tiger. The scat analysis identified 10 prey species and 81 prey items in the tiger’s diet. Spotted deer was the frequently killed prey species followed by wild boar and barking deer. In terms of biomass consumption, large-sized sambar was on the top. The average weight of the prey killed was 138 kg. The tiger strongly selected sambar and weakly selected small-sized barking deer. Medium-sized prey species (spotted deer and wild boar) were neglected. The large-sized prey and their density were the keys to increasing the tiger population in PNP. The absence of livestock in PNP’s tiger diet suggests it to be a potential area for tiger conservation.