INTRODUCTION: Pancreatitis is one of the most common complications of Endoscopic Retrograde Cholangiopancreatography (ERCP). There are endoscopist related factors and patient related factors that increase the risk of post-ERCP pancreatitis. However, epidemiologic factors that increase the risk of same are not well known. We aim to study the association between various epidemiologic factors especially weekend admission and post- ERCP pancreatitis. METHODS: National Inpatient Sample for years 2009–2013 was used for this study. It is the largest ICD-9 code based inpatient database in the US. ICD-9-CM procedure code 51.10 was used to identify all adults who underwent ERCP. Post-ERCP pancreatitis was identified with ICD-9-CM code 577.0 listed as secondary diagnosis. All hospitalizations with missing age & gender information, or primary diagnosis of pancreatitis were excluded. Mean and percentages were used to summarize continuous and categorical variables respectively. Multivariate logistic regression was used to identify the predictors of post-ERCP pancreatitis. Demographic & hospital characteristics, clinically relevant Elixhauser co-morbidites, pancreatic stent placement, and sphincterotomy were used as covariates for regression model. RESULTS: Total of 140859 ERCP(s) were performed during five years. Of these 18870 (13.4%) patients developed post-ERCP pancreatitis and 430 (2.3%) of these died during the hospitalization. Pancreatic duct stent was placed in 4356 patients and 943 (21.6%) of these patients developed post-ERCP pancreatitis. Demographic, hospital characteristics, and outcomes of patients who developed post-ERCP pancreatitis compared to those who didn't are shown in Table 1. On multivariate regression weekend admission (OR = 1.12, P = 0.01), sphincterotomy (OR = 1.48, P < 0.001), pancreatic stent placement (OR = 1.47, P = 0.01), obesity (OR = 1.45, P < 0.001) were some of the factors associated with increased risk of post-ERCP pancreatitis. Teaching hospitals (OR = 0.81, P < 0.001) were associated with lower risk of pancreatitis. CONCLUSION: Pancreatic stent placement has been shown to be protective for post-ERCP pancreatitis, however, in our study there were higher odds of pancreatitis in patients receiving pancreatic. This was likely because of pancreatic stents being placed in patients felt to be at higher risk of post ERCP pancreatitis. In conclusion, weekend admission was associated with higher risk, and teaching hospitals with lower risk of developing post-ERCP pancreatitis.