Hughes-Stovin syndrome is an exceedingly rare disorder of unknown etiology, and it is characterized by multiple pulmonary artery aneurysms and peripheral venous thrombosis. We report a case of Hughes-Stovin syndrome with complete resolution of pulmonary artery aneurysm after treatment with cyclophosphamide. A 48-year-old man presented with massive hemoptysis, fever, and weight loss of 4-month duration. Computed tomography angiography revealed multiple pulmonary arterial aneurysms of variable sizes in both lung fields. Inferior vena caval thrombosis was also noted. Despite multiple surgical procedures including embolectomy and lobectomy combined with steroid therapy, new aneurysms continued to appear with persistent hemoptysis. Thorough history and physical examination did not suggest any evidence of Behcet's disease. Hughes-Stovin syndrome was subsequently diagnosed. High-dose prednisolone combined with oral cyclophosphamide therapy was initiated. Chest radiography follow-up in 3 months revealed complete resolution of pulmonary aneurysm. No new aneurysm was detected at 15 months of follow-up.