ObjectiveTo investigate the value of nasobiliary cholangiography in the diagnosis of residual common bile duct stones after endoscopic retrograde cholangiopancreatography (ERCP) and the risk factors for residual stones. MethodsA retrospective analysis was performed for the clinical data of the patients who underwent ERCP and nasobiliary cholangiography after endoscopic nasobiliary drainage in Peking University First Hospital from January 1, 2018 to December 31, 2019. The chi-square test was used for comparison of categorical data between groups, and a logistic regression analysis was used to investigate independent risk factors for residual stones. ResultsA total of 366 patients underwent ERCP and nasobiliary cholangiography and 27 patients were suspected to have residual stones, among whom 25 had residual stones confirmed by ERCP. The rate of residual stones after ERCP was 6.8% (25/366), and nasobiliary cholangiography had a positive predictive value of 92.6% (25/27) in predicting residual common bile duct stones. The univariate analysis showed that there were significant differences between the two groups in multiple stones, common bile duct diameter ≥1.5 cm, and mechanical lithotripsy (χ2=5014, 7.651, and 9.670, all P＜0.05). The multivariate logistic regression analysis showed that multiple stones (odds ratio ［OR］=2713, 95% confidence interval ［CI］: 1.002-7.345, P=0.049) and mechanical lithotripsy (OR=9.183, 95% CI: 2.347-35.925, P=0.001) were independent risk factors for residual stones. ConclusionPost-ERCP nasobiliary cholangiography is an effective method to detect residual common bile duct stones. Multiple stones and mechanical lithotripsy during ERCP are independent risk factors for residual stones.