A study of 87 patients surgically treated for renal arterial stenosis revealed that upper abdominal bruits were heard more frequently in patients whose stenosis was due to fibrous disease than to atherosclerosis. A diastolic bruit in a patient with fibrous disease of the renal artery usually indicated a favorable surgical result. Conclusions regarding the prognostic value of diastolic bruits in atherosclerotic renal artery disease must be deferred until a larger number of patients with this finding can be studied. When hypertension of less than 3 year's duration was combined with presence of a diastolic bruit, 17 or 18 patients had a favorable surgical outcome. An abdominal bruit should be carefully sought for in all patients evaluated for hypertension; when found, should be characterized acurately, because of the important diagnostic and prognostic information it may provide.