Background: The Common Channel Syndrome (CCS) is defined as the union of the biliary and pancreatic ducts outside of the duodenal wall with a common duct more than 15 mm long. It is classified morphologically in types 1 and 2, whether it is the biliary or the pancreatic duct the one that predominates. CCS is uncommon in Western countries. It is described particularly in children and has not yet been reported in Chile. Aim: To report the frequency of CCS among patients subjected to endoscopic retrograde cholangiopancreatography (ERCP). Patients and methods: Between 1992 and 1998, 1860 ERCPs were performed for the diagnosis of biliary or pancreatic diseases. Results: In six patients (0.35%) a CCS was diagnosed (3 type 1 and 3 type 2). All patients presented with pain and three with jaundice. Four patients had a previous cholecystectomy, three due to cholelithiasis and one due to gallbladder cancer. A common bile duct resection and bilioenteric anastomosis was done in three patients with a favorable outcome. Two patients with an advanced age and one with a gallbladder cancer, were not operated. Conclusions: CCS was found in 0.35% of patients subjected to an ERCP. It frequently presents in association with one or more bilio-pancreatic diseases: cholelithiasis, choledocolithiasis, cholangitis, pancreatitis and gallbladder cancer. Resection of the common bile duct and a bilio-enteric anastomosis is proposed as the surgical treatment. (Rev Méd Chile 2001; 129: 299-302)