As CT is often the initial imaging method in the evaluation of suspected complications of abdominal aortic aneurysm, especially rupture of the aneurysm, it is important to be aware of other less common complications that can be detected by CT. A patient with an aortocaval fistula and renal venous hypertension is discussed. The constellation of CT findings that suggest this diagnosis is described as is the angiographic correlation. Awareness of these CT findings, including early equivalent enhancement of the inferior vena cava and aorta; enlarged, poorly functioning kidney; and perirenal "cobwebs," will lead to the appropriate confirmatory angiographic studies.