To accurately determine the in vivo orientation of the origin of the renal arteries from the aorta relative to a fluoroscopic bony landmark for optimal diagnostic arteriography and renal artery stent placement.One hundred sixty abdominal computed tomography (CT) scans of patients in eight age groups (20–90 years) were reviewed to determine the angle of the origins of the renal arteries from the aorta relative to the long axis of the L-l spinous process (L1SP).The right renal artery arises ventrally at an angle of 30° (standard deviation [SD] = 15°) from a plane orthogonal to the long axis of the L1SP. The left renal artery arises dorsally at an angle of 7° (SD = 13°) relative to the same plane.The optimal initial angle for angiographic evaluation of the origin of the renal artery and for renal artery stent placement is 30° left anterior oblique (LAO) relative to the L1SP for the right renal artery and 7° LAO for the left renal artery. Unfortunately, there is variability in the angle of the renal artery origins from the aorta which cannot be controlled for using this technique. In some patients, additional views will be necessary to optimally depict the origins of the renal arteries.