We described a case of pulmonary hemorrhage associated with myeloperoxidase-antineurophil cytoplasmic antibodies (MPO-ANCA) without renal involvement during propylthiouracil (PTU) treatment. A 36-years old female was admitted to our hospital because of progressive dyspnea with hemosputum after flu-like symptom and episcleritis. She had been receiving PTU for three years to Graves' disease. On admission her chest Xp showed bilateral massive infiltrative shadow and bronchofiberscopy demonstrated pulmonary hemorrhage. MPO-ANCA and anti-thyroperoxidase antibodies were positive, but she had normal urinalysis and normal renal function. After withdraw of PTU, pulmonary hemorrhage disappeared. But 15 days later pulmonary hemorrhage recurred associated with high MPO-ANCA titer. Corticosteroid bolus therapy and oral cyclophasphamide administration improved pulmonary hemorrhage, and MPO-ANCA titer also decreased. It is suggested that MPO-ANCA and PTU might be closely related to the pathogenesis of pulmonary hemorrhage in this case.