Two children with aortic aneurysm are reported. In one, a 12-year-old girl, aortic dissection resulted in rupture, severe anemia, cardiac tamponade and death. Cystic medionecrosis was seen on necropsy. In the second, a three-year-old boy, a tuberculous etiology was considered on the basis of a positive Mantoux test, exudative pericarditis and significant improvement, clinical and radiological, following antituberculosis therapy. In both patients, there were no features of Marfan's syndrome or its forme fruste.