Three patients, two Moroccan men aged 27 and 25 and a Turkish man aged 25, presented with haemoptysis caused by pulmonary aneurysm. The aneurysms had formed as a complication of Behçet's disease. Two of them were treated with high doses of corticosteroids. One man recovered and another died as a consequence of massive haemoptysis. The third man underwent emergency thoracotomy and pneumectomy due to massive haemoptysis. Postoperatively he was treated with cyclosporine resulting in full recovery. Behçet's disease is a multisystem vasculitis characterised by orogenital ulcerations and uveitis. In a minority of cases pulmonary aneurysms develop, often causing massive haemoptysis. Aneurysms are often accompanied by venous thrombosis. Treatment consists of immunosuppressive therapy. Nevertheless a considerable number of patients die following massive haemoptysis.