This prospective study was aimed at comparing the diagnostic accuracy of Magnetic Resonance Angiography (MRA) with that of color-Doppler ultrasonography (color-Doppler US) in the detection and assessment of abdominal aortic aneurysms. Twenty patients with abdominal aortic aneurysms underwent MRA, color-Doppler US, digital subtraction angiography (DSA) and Computed Tomography (CT) on three consecutive days. Fourteen patients underwent surgical repair of the aneurysm. MRA and color-Doppler findings were compared with DSA, surgical and pathologic findings, which were considered as the gold standard. In the 6 patients who refused surgery, CT and DSA were considered the gold standard. MRA always correctly assessed the size and site of the aneurysm, the involvement of the renal and common iliac arteries, the retroarotic course of the left renal vein, the thrombotic component and calcifications. Color-Doppler US always correctly assessed the size and site of the aneurysm, the thrombotic component and calcifications and the involvement of the iliac arteries. In one case color-Doppler US failed to demonstrate the involvement of the renal arteries and the retroaortic course of the left renal vein. Our preliminary results suggest MRA as the best non-invasive technique to study abdominal aortic aneurysms.