Aortitis is a general term denoting inflammation of the aortic wall. Various infectious and non-infectious diseases can be complicated by aortitis; in addition, isolated idiopathic aortitis has also been described. In a 12-year nationwide Danish population-based study, the prevalence of aortitis among 1,210 resected thoracic aorta samples was 6.1%, with nearly three-quarters of cases being idiopathic. Identified risk factors for aortitis included advanced age, a history of connective tissue disease, diabetes mellitus, and heart valve pathology. As in virtually all pathological studies, this study has a bias toward reporting the most severe cases of aortitis requiring surgical repair.