Background: Despite proven clinical benefit, there are no studies that have examined the relationship between pancreatic stent caliber and its impact on PEP [post-endoscopic retrograde cholangiopancreatogram (ERCP) pancreatitis] in high-risk patients. Aim: To study the relationship between stent caliber and PEP rates in patients with confirmed sphincter of Oddi dysfunction (SOD). Methods: A retrospective review was conducted of ERCP's in patients with SOD from 2002 to 2012 from a prospectively maintained, Institutional Review Board approved database. Results: A total of 243/7659 (3.2%) patients underwent 3Fr or 5Fr pancreatic stent placement following sphincterotomy for manometry-proven SOD. Of these, 133 (54.7%) underwent 3Fr stent placement, while 110 (45.3%) underwent 5Fr stent placement. There was no significant difference between the two groups in terms of baseline characteristics, demographics, and previous cholecystectomy. Cannulation and stent placement success rates were 100% in both groups. There was no significant difference in rates of PEP and overall complications, 12% versus 12.7%; P=0.89 and 13.5% versus 15.5%; P=0.54, between the 3Fr and 5Fr cohorts, respectively. There were more mild PEP rates recorded in 5Fr group (93% vs 56% P=0.0549) that was not statistically significant. Conclusions: There appears to be no relationship between stent characteristics and the risk or severity of PEP in patients with manometrically proven SOD. © 2014 Journal of Gastroenterology and Hepatology Foundation and Wiley Publishing Asia Pty Ltd.