ERCP and cholangiography during surgery (SC) are compared in regard to their usefulness in 100 patients in whom cholecystectomy was performed because of gallstones. The biliary tree was visualized in 73% of patients with ERCP and in 85% with SC 20 patients presented stones in the common bile duct (CBD), of these 19 had previous signs or symptoms clinical history, laboratory, ultrasonography) that suggested this diagnosis, of the rest of the patients (80) without CBD stones only 7 had signs or symptoms that suggested this diagnosis, 4 of these patients had normal cholangiograms and 3 had "odditis". So in 73 patients without symptoms suggestive of CBD stones, preoperative or intraoperative cholangiography was probably not necessary. We consider that it is convenient to perform ERCP only in those patients with gallstones who have clinical findings suggestive of CBD or pancreatic problems (history, laboratory, ultrasonography). Cholangiography during cholecystectomy would be indicated in patients with small gallstones, the finding during operation of a dialted CBD or palpation of stones in the CBD and when ERCP fails in a patient with suggestive symptoms or when there is doubts with the ERCP findings.