Objective: To analyze the risk factors for post-endoscopic pancreatitis (PEP). Background: PEP occurs in 4%-42% of patients, depending on their risk factors. Over 56 risk factors were analyzed, but only 4were found to be repeated in most studies. Study: A single-center retrospective study analyzing 402 consecutive patients with naïve papillae who underwent Endoscopic Retrograde Cholangiopancreatography (ERCP) was conducted. The significance of 14 potentially new risk factors was evaluated, and it was found that they were associated with the level of bile duct stenosis, papilla anatomy, bleeding during sphincterotomy, endoscopic bleeding control, and pathological examination. Furthermore, 13 of the most frequently published risk factors were re-analyzed. Results: Five risk factors (containing two new ones) were significant with the following univariate and multivariate regression values: flat papilla (odds ratio [OR] 5.1, p=0.0049; OR 4.59, p=0.0244) and bleeding during endoscopic sphincterotomy (OR 3.58, p=0.148; OR 4.07, p=0.0257), and significance of the three already known risk factors was confirmed: age <40 years (OR 6.89, p=0.0139; OR 4.96, p=0.0139), common bile duct (CBD) diameter < 9 mm (OR 5.35, p=0.0007; OR 3.98, p=0.0203), and difficulty in cannulation (OR 3.2, p=0.0298; OR 7.72, p=0.004). Conclusion: This study reaffirms the risk of PEP associated with age, difficulty in cannulation, and CBD diameter. It also identifies two new risk factors: flat papilla and bleeding during sphincterotomy. These results suggest the need for a change in ERCP methodology in patients with these risk factors, but this finding requires confirmation in subsequent studies.