A 60 year old man was admitted with acute back pain followed by hoarseness. An aneurysm of the ductus arteriosus Botalli was diagnosed and an operation was recommended because of the high risk of complications such as rupture, embolism, or infection. The patient and his family refused surgery, however. The patient died suddenly of a rupture of the aneurysm a year later; necropsy confirmed the diagnosis. Several diagnostic methods were used and enhanced computed tomography gave the best representation of the aneurysm as it was seen at necropsy. This case indicates that enhanced computed tomography is probably the most useful investigation in patients with this type of aneurysm and it confirms the importance of an aneurysmectomy.