Clinico-instrumental examination of 226 patients showed that there were no fatal outcomes directly after endoscopic papillosphincterotomy, the number of complications was approximately the same as after transduodenal operations on the major duodenal papilla but they took a much easier course. The high effectiveness of an endoscopic operation was confirmed in the immediate postoperative period (absence of biliary hypertension, jaundice, pancreatitis, cholangitis). In the late-term periods after EPST restenosis was rarely encountered (3.9%); duodeno-biliary reflux caused no serious disorders, while the functional activity of the sphincter Oddi which had been operated on was partly maintained in 84.2% of patients.