To describe the morphologic features so the process can be easily identified during surgery, we studied 34 patients with cardiovascular syphilis, 32 of whom underwent excision and replacement of the ascending aorta or aortic valve or both. Of the 34 patients, 22 were treated at Baylor University Medical Center from 1998 to 2008 and 12 at non–Baylor University Medical Center hospitals from 1958 to 1987. In all 34 patients, the tubular portion of the aorta was diffusely thickened and the sinus portion of the aorta was apparently uninvolved. The process involved all 3 layers of the aorta, with thickening of the adventitia, mainly by fibrous tissue. Within the fibrous tissue were collections of plasma cells and lymphocytes, focal destruction of the media without thickening, and marked thickening of the intima by atherosclerotic-appearing lesions. Serologic tests for syphilis were done in only 14 patients (41%) and were positive (reactive) in 6 (43%) of them. The ascending aorta, however, was similar in all 34 patients. In conclusion, cardiovascular syphilis has not disappeared. Its identification during surgery can prompt appropriate antibiotic therapy postoperatively. Although the serologic test results for syphilis might be negative, antibiotic therapy is recommended for patients with panaortitis requiring resection of the ascending aorta with or without aortic regurgitation.