This Note reports on studies of the appropriateness of use of coronary angiography, carotid endarterectomy, and upper gastrointestinal tract endoscopy and its relationship to geographic variations in the rates of use of these procedures. The authors selected geographic areas of high, average, and low use of these procedures and randomly sampled Medicare beneficiaries who had received one of the procedures in 1981. They determined the indications for the procedures using a detailed review of medical records and used previously developed ratings of appropriateness to assign an appropriateness score to each case. Differences among sites in levels of appropriateness were small. For example, in the high-use site for coronary angiography, 72 percent of the procedures were appropriate, compared with 81 percent in the low-use site. Coronary angiography was performed 2.3 times as frequently in the high-use site compared with the low-use site. Under the conditions of this study, the authors did find significant levels of inappropriate use: 17 percent of cases for coronary angiography, 32 percent for carotid endarterectomy, and 17 percent for upper gastrointestinal tract endoscopy. They conclude that differences in appropriateness cannot explain geographic variations in the use of these procedures.