A 40-year-old Chinese man was admitted for haemoptysis and progressive deep vein thrombosis involving the inferior vena cava (IVC) despite anticoagulation. An IVC filter had been placed earlier at an outside hospital. CT angiography revealed two pulmonary artery aneurysms. The patient was found to have a history of oral and genital ulcers, uveitis and erythema nodosum, thus meeting criteria for Behçet's disease. Other causes of the haemoptysis and thrombophilia were excluded. He underwent successful coil embolisation of the pulmonary artery aneurysms and responded well to immunosuppressive therapy with cyclophosphamide and steroids. Anticoagulation was cautiously continued to limit the long-term risk of secondary thrombosis from his IVC filter. The patient remains well 5 months after initiation of immunosuppressive therapy. Making a diagnosis of Behçet's disease in the setting of thrombosis is crucial, as treatment must include immunosuppression, and, thus, fundamentally differs from the management of most other thrombotic disorders.