BACKGROUND: The aim of the study was to prospectively compare the diagnostic performance of CT angiography (CTA) with MR angiography (MRA) in the preoperative assessment of living renal donors. METHODS: Forty-eight potential living renal donors (mean 51 years, 29-67 years) underwent multislice CTA and gadolinium-enhanced MRA. Six potential donors were excluded. Forty-two donors underwent minimal invasive retroperitoneoscopic nephrectomy (left 36, right 6) and their datasets available for analysis independently performed by two blinded radiologists. The surgical status served as gold standard. RESULTS: In 42 donors (84 kidneys), CTA identified 63 kidneys with 1 artery (MRI 61), 19 with 2 arteries (MRI 20), one with three arteries (MRI 2), and one with four arteries (MRI 1). Considering only the side with the surgical status available for verification, both CT and MRI correctly characterized 35 of 36 donors with a single renal artery and five of six with one supernumerary artery. Two false positives were two arteries suggested as supernumerary both in CT and MRI not confirmed during surgery. CTA and MRA both correctly identified three accessory renal veins in two donors. CONCLUSION: CTA and MRA had the same accuracy for characterization of renal vasculature in the preoperative assessment of living renal donors.