Some chronic renal failure patients maintained on dialysis have uncontrollable hypertension. Those with elevated renin levels require bilateral nephrectomies prior to kidney transplant to avoid nephrosclerosis. The morbidity and mortality from surgical nephrectomies are high. In 2 such patients we embolized the renal arteries with gelfoam and successfully occluded all the major vessels. One patient became normotensive. The second remained hypertensive and had increased renin levels, probably on the basis of ischemia. Subsequent surgical nephrectomies demonstrated completely occluded segmental branches but only focal areas of infarction. Collateral blood supply determines the success of the procedure.