trospective study was to identify risks for adverse events, procedure failure, and prolonged courses in pediatric patients undergoing ERCP. Methods: Pediatric patients who had an ERCP at one of our academic centers were identified by query of their electronic medical records. Pre-procedure and post-procedure data were collected with ERCP-related adverse events defined according to the consensus criteria developed by Cotton et al 2010. Results: Between January 2004 and January 2021, 287 children had a total of 716 ERCPs. The procedure success rate was 95.5% with no mortality and an adverse event rate of 12.7%. Younger age was associated with increased case complexity, increased adverse events, and an increased rate of repeat ERCP. Case complexity score correlated with increased procedure time (P < 0.001) and increased adverse events (tau 0.24, P < 0.01); stent removal and pancreatic stenting were more likely to precede an adverse event. Pancreatitis, pancreatic divisum, and pancreatic s