Behçet's disease is a systemic vascularitis generally involving the venous system. Many organs may be involved, but pulmonary localizations are uncommon. We report 5 cases of pulmonary artery aneurysms observed in a series of Behçet's disease collected over a 10-year period. All patients were males, age range 18-41 years. Hempotysia was the inaugural event in all cases. Behçet's disease was recognized in only 2 of the patients initially. The diagnosis was made after recognition of the pulmonary artery aneurysms in the others. Chest x-ray showed round perihilar opacities varying in number from 2 to 4. Computed tomography with vascular opacification was performed in 4 patients and confirmed the aneurysmal nature of the opacities. Angiography was performed in 3 cases. Medical treatment with corticosteroids and/or colchicine was prescribed in all cases. One patient had left inferior lobectomy. In one case regression of the aneurysms precluded embolization. Two patients refused surgery and in one, surgery was not retained due to the large number of aneurysms. Outcome was fatal in one patient who died after cataclysmic hemoptysia. These findings underline the uncommon nature of pulmonary aneurysms in Behçet's disease and the diagnostic difficulties encountered in absence of specific signs as well as the poor prognosis of such localizations.