Anecdotal evidence suggests the endangered Great Hornbill (Buceros bicornis) needs mature, large old-growth trees for nesting. We tested this hypothesis by measuring vegetation characteristics at 24 nest sites in southern India and compared these data with that obtained from equal numbers of unused forest sites. Characteristics significantly different from surrounding forest at hornbill nesting sites were several properties related to size of trees. The nesting habitat characteristics of the species stress the importance of mature forests with emergent trees for nests of the Great Hornbill. Trees used by Great Hornbills for nests, compared to unused trees, averaged 18.5 m taller, 0.85 m greater in diameter, and emerged more above the forest canopy by 12.7 m. Canopy height, canopy cover, and number of large trees >75 cm DBH were greater at nest sites than at unused sites by 5.79 m, 3.15%, and 1.63 trees, respectively.