BACKGROUND Endoscopic retrograde cholangiopancreatography (ERCP) is a valuable study in the approach to diseases of the biliary and pancreatic ducts. It was first used for diagnostic purposes, but today its use is mainly therapeutic. It can present a variety of complications. AIMS To determine the frequency of complications and the risk factors associated with ERCP. MATERIAL AND METHODS A prolective study was carried out to analyze ERCP that was performed on 1.145 patients over a 10-year period of time (2.002-2.011). Complications were determined at the time of the procedure, through the personal communication of relatives, and/or when the patient was admitted to the emergency room. Follow-up was carried out for one month after ERCP in the out-patient service of the Department of Gastroenterology. Complications were evaluated with a multiple logistic regression model. RESULTS The sample included 1.145 patients. Mean age was 55,3 years (SD=18,7; CI 95%: 54,2-56,3). Women made up 60,5% (n=693) of the study participants. Therapeutic endoscopy was performed in 51,0% of the total number of procedures. Complications presented in 2,1% (n=24) of the patients; the most frequent was hemorrhage (n=14, 1,2%), followed by acute pancreatitis (n=6, 0,5%), respiratory distress (n=3, 0,3%), and cholangitis (n=1, 0,1%). There was a 1,4 times higher complication risk in patients that underwent precut/sphincterotomy, adjusted by age (CI 95%: OR 1,02-5,43; p=0,045). CONCLUSIONS This study shows a complication frequency similar to that published by other authors. However, this figure could be further reduced if ERCP were performed only for therapeutic purposes by highly qualified endoscopy physicians.