The pulmonary arterial anatomy in 44 patients with Takayasu's arteritis was examined by intravenous digital subtraction angiography (IV-DSA) on an outpatient basis using centrally delivered, small-volume, bolus injections of an ionic, water soluble contrast medium. Diagnostic pulmonary angiograms were obtained in 42 patients (95.4%) without complication. Angiographically evident pulmonary arterial involvement was seen in six patients (14.3%). The pulmonary involvement was not suspected clinically in any patient and the chest radiographs were abnormal in only two patients (33%). The angiographic spectrum of systemic arterial involvement was the same irrespective of the presence or absence of pulmonary arterial involvement. The pulmonary arterial pressures were measured in two patients with abnormal pulmonary angiograms and were found normal. Follow up IV-DSA in one of these patients 16 months after immuno-suppressive therapy showed no change in the pulmonary angiographic picture.