We compared diets of little owls (Athene noctua) and long-eared owls (Asio otus) in the Minqin Desert in northwestern China. Based on prey numbers, little owls fed mainly on mammals (51.0%) and beetles (46.9%), whereas long-eared owl fed almost exclusively on mammals (96.4%). Based on biomass, both species fed mainly on mammals. Mus musculus, Cricetulus barabensis and Meriones meridianus were the three most common mammals taken by both species. Seasonal variation was found in the diets of both species. Food niche breadth was 3.4 for little owls vs 2.9 for long-eared owls. Dietary overlap between the two species was 49.6%, but varied from 4.0% in April to 96% in January. Dietary overlap of mammals was 97.9%, indicating that both owls fed on similar rodent assemblages. Mean mass of prey was 25.8 ± 22.7 g for long-eared owls and 15.5 ± 22.7 g for little owls. The mean length of tibias of mammals in pellets also indicted that, on average, long-eared owls (18.1 ± 5.6 mm) took larger prey than little owls (16.2 ± 4.7 mm).