Sixteen patients with Takayasu's (idiopathic) arteritis constituted 0.09% of the autopsy population during a 26-year-period. Systemic hypertension was present in 14 patients. All portions of the aorta as well as its major branches were involved in the 16 patients. Thrombi were scanty, but intimal fibrous plaques and multiple aneurysms were frequent. Three patients showed the unusual occurrence of segmental involvement of major epicardial coronary arteries with coronary aneurysm formation in two of these patients. Thirteen patients showed residual evidence of inflammation. Coexistent tuberculosis, distant from the arterial lesions, was present in 37.5% of our patients. One patient showed healed pulmonary arteritis. The cause of the disease remains obscure. Emphasis is laid on the application of strict criteria to differentiate specific forms of arteritis, eg, rheumatic mesoaortitis from Takayasu's arteritis.