Thoracic aortic aneurysm formation is a known complication of late syphilis. Large aneurysms may cause symptoms via mass effect. When aneurysms compress the pulmonary artery, pulmonary arterial hypertension and right heart failure may result. We report the case of a 76-year-old man who presented with right heart failure secondary to an 11-cm syphilitic thoracic aortic aneurysm, and discuss the evolving epidemiology, complications, diagnosis and management of syphilitic aortitis.