It is well inferred that symptoms caused by syphilitic aneurysms of the aortic arch are probably of only two years' duration, their limitation being imposed by death of the patient. Kampmeier3 examined 188 such cases and found that only 18 of these lived longer than two years. In the past 12 years, there has been a vigorous attempt by surgical means to alter this unfavorable prognosis. In 1958, DeBakey, Cooley, Crawford, and Morris1 reported seven years experience involving 50 aneurysms of the aortic arch, 35 of which were syphilitic in origin. Their operative mortality was 56%. This mortality figure is thought still generally representative by Gaertner, Spencer, and Bahnson2 who reviewed the subject in 1962. It is because of this high mortality and because of the technical aspects of such surgery that we wish to present a single case of syphilitic aneurysm of the aortic arch and