Résumé : Background and Aims: The ideal pancreatic stent to prevent post-ERCP pancreatitis (PEP) has yet to be determined. The aim of our study was to assess the relative benefit of 4-Fr versus 5-Fr stents in a population at high risk for post-ERCP pancreatitis, and the relative frequency of spontaneous migration. Patients and Methods: All patients with prophylactic pancreatic stent (PPS) from 2002 to 2009 were reviewed. Patients were classified into two groups according to stent size and compared based on outcome; spontaneous migration or endoscopic removal. Results: A total of 346 PPS were placed in 308 patients (224 women, 84 men). The average age was 48.9 years. The most common indication for PPS was sphincter of Oddi dysfunction. Needle knife papillotomy was the most common procedure performed. Forty-seven patients had PEP, 4 Fr (14.6%) and 5 Fr (12.9%), with only one case of severe pancreatitis. Factors associated with higher rates PEP were younger age and pancreatic sphincterotomy. Complete follow-up was not available in 37 patients. Spontaneous migration was demonstrated in 115 of the 4 Fr (95.8%) and 134 of the 5 Fr (68.7%). The remaining 66 (five from the 4 Fr and 61 from the 5 Fr), were removed by endoscopy. The mean delay to demonstrate spontaneous migration was 34.2 days. Conclusions: PPS in high-risk patients reduced the risk of post-ERCP pancreatitis and nearly eliminated severe pancreatitis. No significant difference between the 4 Fr and 5 Fr in reduction of post-ERCP pancreatitis was observed. However, spontaneous migration was more frequent with the 4-Fr stent. © 2011 Springer Science+Business Media, LLC.