Although carotid endarterectomy is a controversial and frequently performed surgical procedure, little is known about the clinical appropriateness of its use in actual practice. Are the majority of procedures performed for highly accepted clinical reasons? We studied the clinical appropriateness of 107 procedures performed on 95 patients in 1981 in five Veterans Administration teaching medical centers. Standards for judging appropriate use were based on the recommendations of a multidisciplinary panel of nine physicians. Fifty-five percent of the procedures studied were judged clearly appropriate, 32% equivocal, and 13% clearly inappropriate. The rate of serious operative complications was 5.6% These results suggest that carotid endarterectomy is overutilized within at least some segments of the Veterans Administration population.