Group-hunting predators theoretically benefit from hunting together through increased prey returns; however, studies on lions suggest food is not enough. The dhole is one such group hunter; however, its predatory role within Asia's large predator guild is less well known than other members. We tested whether dholes exhibit preferential predation, and determined the drivers of prey choice and whether pack size affected diet to ascertain the fundamental resources required for the species' conservation, given lack of a prey base is the primary threat to this species. We reviewed the literature and found 24 studies from 16 sites from throughout the species extant range that reported on 8816 records (scat + kills) of 19 species. Jacobs' index revealed that sambar Rusa unicolor, chital Axis axis and wild boar Sus scrofa contribute almost two-thirds of the food biomass of the dhole, with sambar being significantly preferred. Sambar are at the upper end of the accessible prey spectrum (30–235 kg), and are marginally above the preferred weight range of 130–190 kg. The accessible prey spectrum extensively overlaps with leopards and tigers in Asia and reflects the extensive dietary competition within Asia's large predator guild, as tigers also preferentially prey on sambar and leopards completely overlap in the accessible prey with dholes. Although prey preferences are not affected by pack size, larger packs ultimately take larger prey. This study documents for the first time the critical prey resources necessary for the conservation of dholes in Asia, and highlights the degree of competition potentially occurring across dhole distribution range.