We used magnetic resonance imaging (MRI) to evaluate the CNS, and confirmed CNS lesions histologically, in 3 psittacine birds with neurologic signs. One bird was recumbent as a result of non-ambulatory paraparesis, and 2 birds were ataxic with impaired proprioception. In all 3 cases, imaging was performed, and infectious diseases were excluded in cases 1 and 2. In case 1, a large mass arose from the left lung; in case 2, a multinodular coelomic mass encompassed the left caudal pulmonary area to the left cranial renal pole; and in case 3, a diffuse hyperintensity affected the lumbar spinal cord. In the first 2 cases, masses invaded the vertebral canal, causing spinal cord compression. All 3 birds were euthanized given the poor prognosis, and postmortem examinations were performed. The final diagnoses were pulmonary adenocarcinoma in cases 1 and 2, and granulomatous and lymphocytic leptomeningitis caused by Mycobacterium genavense in case 3. MRI enabled visualization of the lesions in the affected area of the CNS, and MRI findings were confirmed by histopathology.