The evidence presented by the nine cases described in this paper indicates that primary arteritis of the aorta is a single clinico-pathological entity of which Takayashu's syndrome is a part. Different segments of the aorta may be affected resulting in a variety of symptom complexes. In this series, the mode of presentation was hypertension consequent on renal artery stenosis. Early diagnosis is important and surgical treatment is indicated to relieve the hypertension which carries an immediately serious prognosis.