Vasculitis is the primary pathological feature of Behçet's disease and in which pulmonary arterial aneurysm formations are rare but serious complications representing poor prognosis. There is no agreement on how to treat major venous and arterial disease. The use of steroids alone or corticosteroid treatment supplemented with cyclophosphamide or azathioprine is still controversial. We present three young male patients with Behçet's disease with aneurysms in the pulmonary arteries. In two of them, cyclophosphamide was the first choice of treatment, but this was ceased due to side effects. All three patients were then treated with azathioprine (2 mg/kg per day) and methylprednisolone (1.5 mg/kg per day). All three showed clinical improvement. Regression was observed radiologically in two (one minimal and the other complete). No complication related to therapy was encountered. Steroid therapy supplemented with azathioprine may be a good choice for treatment of pulmonary arterial aneurysms in Behçet's disease.