To observe the clinical features of Takayasu's arteritis and evaluate the incidence and sites of coronary arterial involvement in Takayasu's arteritis, clinical observations were made in 99 patients who were diagnosed as Takayasu's arteritis by clinical features and aortographic findings in Seoul National University Hospital from August 1971 to July 1989 Coronary arteriographies were performed prospectively in 30 patients with Takayasu's arteritis since March 1987. The results were as follows: 1) In 99 cases of Takayasu's arteritis, 15 were male and 84 were female. The male to female ratio was 1:5.7, the mean age was 29.5, and 63% of those studied were under the age of 30. 2) The following were the presenting clinical symptoms and signs in decreasing order of frequency: headache(69%), weak or nonpalpable pulse(68%), carotid or abdominal bruit(55%), Dyspnea on exertion(51%), hypertention(48%), and dizziness(43%). 3) Aorta or arterial involvement in decreasing order of frequency: left subclavian artery(62%), abdominal aorta(58%), right subclavian artery(38%), descending thoracic aorta(37%) and left renal artery(35%). 4) Using Ueno's classification, 29(29%) were Type I, 22(22g) were Type II, and 48(48%) were Type III. Type IV or pulmonary arterial involvements were seen in 11(33%) out of 33 patients. 5) In a prospective study using coronary arteriography, 8(27%) out of 30 patients of Takayasu's ateritis showed coronary involvement. Among the 13 lesions of coronary arterial narrowings in 8 patients with coronary involvements, there were 3 ostial lesions, 5 proximal and 5 middle or distal lesions. 6) Frequently there were no cardiac symptom in patients with Takayasu's arteritis who had coronary arterial lesions, and a myocadial infarction or congestive heart failure may be the first sign of the coronary arterial narrowing.