Background: Our aim was to assess the influence of the skill and experience of the endoscopist on the success and risk of endoscopic sphincterotomy techniques. Methods: The outcome of all endoscopic sphincterotomies (n = 1335) carried out between 1988 and 1995 were retrospectively analyzed with respect to the endoscopist performing the procedure. Endoscopists were differentiated according to whether they had previous experience with endoscopic sphincterotomy techniques (n > 100) and the frequency of endoscopic sphincterotomy during the study period (>40, 26 to 40, 10 to 25, <10 per year). Results: Indications for endoscopic sphincterotomy techniques and technical execution had only a minor influence on the results of endoscopic sphincterotomy and were comparable for the individual endoscopists. The overall success rate of endoscopic sphincterotomy was 94.4% and did not significantly differ among the endoscopists. The overall complication rate of endoscopic sphincterotomy was 7.3%. Endoscopists learning endoscopic sphincterotomy techniques with a case frequency of less than 10 procedures per year had a consistently high complication rate (10.5%). Those learning endoscopic sphincterotomy techniques with a case frequency of more than 25 procedures per year had an above-average complication rate for their first 40 endoscopic sphincterotomy procedures and a significant decrease in complication rate as the number of procedures increased. The complication rate for experienced endoscopists was 7.7%. There were distinct and, in one case, significant differences in complication rates between individual endoscopists (11.5% vs. 4.8%, p = 0.01). However, when corrected for multiple testing, there were no significant differences at the p < 0.05 level. The endoscopic sphincterotomy frequency of the endoscopist was the only significant risk factor for complications. Endoscopists with a frequency of more than 40 procedures per year had a significantly lower complication rate (5.6%) than endoscopists with a lower case frequency (9.3%, p < 0.05). Conclusions: A low endoscopic sphincterotomy frequency is, even for endoscopists with previous experience with the procedure, a risk factor for complications after endoscopic sphincterotomy. The learning of endoscopic sphincterotomy techniques requires a minimum of 40 procedures, but also after 100 procedures a further decrease of the complication rate can be expected.