A 16-yr-old female blue and gold macaw (Ara ararauna) was presented with an acute history of lethargy, inappetance, ataxia, and paralysis. The bird had rapidly progressed from a normal state to complete inability to perch or ambulate within a 48-hr period. Neurologic examination revealed bilateral hind limb paresis with upper motor neuron signs present in both legs and the vent. Radiographs identified multiple nodular soft-tissue opacities within the cranial coelomic cavity and a single nodule superimposed with the thoracic spine. The bird was euthanized and submitted for necropsy, which revealed a primary pulmonary adenocarcinoma with multiple sites of osseous metastasis, including the vertebrae, and subsequent spinal cord compression. This is the first report of pulmonary adenocarcinoma in this species, although reports of similar tumors in other psittacines have been published. This report, along with others previously published, suggests that vertebral metastasis of primary pulmonary tumors may be more common in psittacine species than previously recognized and, as such, should be considered as a differential diagnosis in psittacine birds exhibiting signs of neurologic dysfunction attributed to a spinal cord lesion.