A 25-year-old, male mealy Amazon parrot (Amazona farinose) with a history of polycythemia, hepatomegaly, and epistaxis was evaluated for progressive lethargy and anorexia. Clinical laboratory testing revealed severe polycythemia (71%), hypophosphatemia (1.6 mg/dL), and mild hypokalemia (2.8 mEq/L). Radiographs showed marked hepatomegaly and loss of air sac space. Despite supportive treatments, the bird's condition deteriorated, and it developed ataxia, was unable to fly, and became oxygen dependent. An echocardiogram, including an air bubble study, revealed a right-to-left atrial shunt and presumed pulmonary arterial hypertension. The bird was started on periodic phlebotomy (5–10 mL/kg q6wk) to reduce packed cell volume and sildenafil citrate (2.5 mg/kg PO q8h) for treatment of suspected pulmonary arterial hypertension. One week later, the patient was weaned off oxygen, and 24 days after initial presentation, the parrot was returned to its outdoor exhibit. Intermittent periods of increased respiratory rate and effort have been reported but have resolved without additional treatments. Epistaxis, once common in this bird, has not been noted since initiating treatment with sildenafil citrate 15 months ago.