A 33-year-old male great hornbill (Buceros bicornis) presented with a roughened fissured rostral casque. Physical examination revealed a softened rostral casque and diagnostic tests indicated a squamous cell carcinoma. A course of photodynamic therapy was begun in which cytotoxic oxygen radicals were generated to destroy tumor cells. Two courses of photodynamic therapy reduced the size and spread of the tumor initially but failed to eliminate the cancer. Upon physical deterioration and progression of the neoplasia, the bird was euthanized.