The Great Blue Turaco (Corythaeola cristata) has been raised in captivity for over a hundred years, but their susceptibility to infectious disease is very poorly documented. The macroscopic, histopathologic, and ultrastructural changes in the respiratory tract of nine Great Blue Turacos (Corythaeola cristata) who died in captivity were investigated. Macroscopically diffuse granulomatous lesions were observed in the lung and the associated air sacs, with a grey-greenish mold on their inner surface. Histopathologic examination revealed widespread necrosis in the lungs associated with vasculitis. Microthrombi were observed in the blood vessels suggesting disseminating intravascular coagulation. Intra-alveolar hemorrhage and infiltration with macrophages, plasma cells, epithelioid cells, and multinucleate giant cells were observed. PAS staining showed hyphae and conidia, While, Ziehl-Neelsen stain was negative. Transmission electron microcopy examination revealed the presence of Aspergillus fumigatus conidia invading the pulmonary tissue as semilunar spores within the alveolar macrophages. Lysosomal degranulation was also observed in association with fragmented spores suggesting active phagocyosis. Awareness of this condition might improve the rapid and appropriate treatment of exotic birds kept in captivity.