Aneurysm of the abdominal aorta is a serious disease in which progressive enlargement may lead to eventual rupture and death. Rupture usually occurs into the retroperitoneal space, less often into the peritoneal cavity, and rarely into the duodenum or inferior vena cava. This report details the successful surgical treatment in a patient of an aneurysm of the abdominal aorta that ruptured into an anomalous retroaortic left renal vein. Operation was performed without use of blood transfusion. Report of a Case A 55-year-old white man was apparently in good health until April 23, 1967, at which time he experienced the sudden onset of sharp pain in both lumbar areas. He felt weak and had to leave work. The pain exacerbated during the next 24 hours, then subsided during the following two weeks. The pain recurred intermittently during this period and he developed hematuria. A diagnosis of acute rupture of an abdominal