No large studies of cardiovascular syphilis at necropsy have been reported since 1964. We examined at necropsy 90 patients who had characteristic morphologic findings of syphilitic aortitis. None had ever undergone cardiovascular surgery. With the exception of 2 cases seen more recently, the hearts and aortas of the 90 patients were examined and categorized by one of us (W.C.R.) from 1966 to 1990. All 90 had extensive involvement of the tubular portion of the ascending aorta by the syphilitic process, which spared the sinuses of Valsalva in all but 4 patients. The aortic arch was also involved in 49 (91%) of 54 patients and the descending thoracic aorta in 47 (90%) of 52 patients. Syphilis was the cause of death in 23 (26%) of the 90 patients. It was secondary to rupture of the ascending or descending thoracic aorta in 12, severe aortic regurgitation leading to heart failure in 10, and severe narrowing of the aortic ostium of the right coronary artery in 1 patient. Of the 40 patients who had undergone serologic testing for syphilis, 28 (70%) had a positive (reactive) finding. Those patients with a negative or nonreactive test or who did not undergo a serologic test for syphilis had morphologic and histologic findings in the aorta at necropsy similar to the findings of those patients who had had a positive serologic test for syphilis. In conclusion, cardiovascular syphilis has not disappeared. In patients with dilated ascending aortas, with or without aortic regurgitation, a serologic test for syphilis is recommended. If the findings are positive or if characteristic morphologic features of cardiovascular syphilis are suspected, irrespective of the results of the serologic tests, antibiotic therapy appears desirable.