The eastern Junggar Basin in northwest China is a potential area of sympatry for breeding Long-legged Buzzards (Buteo rufinus) and Upland Buzzards (B. hemilasius). However, during a breeding season survey in 2005, the Long-legged Buzzard was the only species recorded present in this semidesert region. The minimum breeding density within our survey area was 0.19 breeding pairs/100 km² and all nests were located either on rock faces or clay cliffs. There was little overlap in the location of Long-legged Buzzard and Golden Eagle nest sites, possibly as a result of interspecific competition. We present here information on clutch size (mean  =  3.3 eggs), brood development, and fledging success (0.7 chicks per breeding pair), as well as on the diet during the breeding season. Mammalian prey, especially the great gerbil (Rhombomys opimus), made up most of the diet of Long-legged Buzzards.