Angiographic findings of 47 patients with pulmonary artery involvement (PAI) in aortoarteritis are described together with the diagnostic evaluation of PAI and its clinical implications. Pulmonary arteriography was obtained by intravenous digital subtraction angiography in 133 patients with aortoarteritis; 45 (33.8%) were found to have PAI. Two patients with PAI, studied by conventional arteriography, are also included. Stenosis and/or occlusion of segmental and/or lobar pulmonary arteries, and subsegmental branches, were the basic angiographic findings in PAI. Pulmonary artery branches in the upper lobes were more commonly affected than those in the lower and middle (lingula) lobes. Bilateral lesions were more common than unilateral ones. Single lobar and segmental lesions were quite rare. Dilatation was uncommon. No main pulmonary artery involvement was detected. Pulmonary artery hypertension, a late complication of patients with PAI, was revealed in 9 of the 46 patients of the present series. If it occurs, PAI becomes a factor effecting the patient's clinical course and prognosis.