Objective To study the relationship between juxtapapillary duodenal diverticulum (JPDD) and pancreaticobiliary diseases, and the effect of JPDD on the diagnosis and treatment of ERCP. Methods A retrospective analysis was performed on data of 1 230 patients who had received ERCP in general surgery departments of Shengjing Hospital of China Medical University from January 2012 to January 2017. The patients were divided into JPDD group (n=360) and non-JPDD group (n=870) according to whether JPDD was found. Patients with JPDD were divided into intradiverticular papilla group (n=41) and non-intradiverticular papilla group (n=319) according to whether the papilla located in diverticulum. The incidence of pancreaticobiliary diseases, success rate of cannulation, success rate of stones removal, and incidence of postoperative complications among each group were compared by using chi-square test or Fisher′s exact probability. P<0.05 was statistically significant. ResultsThe incidence of choledocholithiasis, primary choledocholithiasis and recurrent choledocholithiasis were 87.78% (316/360), 31.11% (112/360), and 6.67% (24/360), respectively, in the JPDD group, and 75.52% (657/870), 19.08% (166/870), and 4.02% (35/870), respectively, in the non-JPDD group. There were significant differences between the two groups (χ2=23.158, P<0.001; χ2=21.068, P<0.001; χ2=3.897, P=0.048). No significant differences were observed in the success rate of cannulation and complete stones removal during the first ERCP session, as well as the incidence of postoperative hemorrhage, pancreatitis and hyperamylasemia between the two groups (all P>0.05). The incidence of recurrent choledocholithiasis in the intradiverticular papilla group and the non-intradiverticular papilla group were 14.63% (6/41) and 5.64% (18/319), respectively, with significant difference (χ2=4.721, P=0.030). There were no significant differences between the two groups in the incidence of choledocholithiasis and primary choledocholithiasis, the success rate of cannulation and complete stones removal during the first ERCP session, as well as the incidence of postoperative hemorrhage, pancreatitis and hyperamylasemia (all P>0.05). Conclusion JPDD is associated with the occurrence of primary choledocholithiasis. JPDD patients, especially the patients with intradiverticular papilla, are more likely to have recurrent choledocholithiasis after ERCP treatment.