A review of 301 consecutive abdominal arteriograms given to patients suspected of having occlusive arterial diseases was conducted. In 99 patients, 35% or more stenosis of the renal artery was demonstrated; of these, 40 showed demonstrable collaterals to the ischemic kidney. The adrenal and lumbar arteries contributed four times more frequently than the periureteric arteries to the collateral circulation. Characteristic ureteral notching from the periureteric artery collateral was noted in only 50% of the cases. Intrarenal collaterals were observed and appeared to contribute to the preservation of the size and function of the affected kidney.