In 26 patients who had undergone renal transplantation, renal arteriograms were obtained to analyze morphologic vascular changes in the region of the anastomosis. The donor kidney had been implanted in the right side of the pelvis in eight and the left side in 18 patients. The renal artery was anastomosed to the external iliac artery in 15 patients and to the internal iliac artery in twelve. Fourteen of 26 patients (54%) were found to have contour irregularities in the region of the anastomosis, either in the external iliac artery (or internal iliac artery, respectively), in the renal artery or both. Well-delineated membrane-like stenoses were seen in seven patients, long segmental stenoses, frequently with poststenotic dilation, in four and the anastomosis was completely occluded in three patients. Arteriography or digital subtraction angiography, respectively, enabled detection of vascular changes in the region of the anastomosis after renal transplantation, thus, rendering guidelines for subsequent interventions to maintain graft viability such as revascularization or percutaneous transluminal angioplasty.