A reported 12% incidence of acute renal failure after angiography prompted this prospective study to substantiate or repudiate this seemingly excessive rate. In 537 consecutive patients undergoing cerebral, abdominal, or peripheral angiography, there was no instance of renal failure following the procedure. The results of this study indicate that when adequate hydration is maintained, angiography does not pose a "significant hazard" of renal failure as previously reported, even in patients with underlying medical problems.