Aims: Evaluate the predictive factors of failure rate of clearing the biliary system from stones at the initial ERCP. Methods: This is a retrospective descriptive and analytical study from September 2002 to September 2021. All patients with bile duct stones, who underwent ERCP with endoscopic sphincterotomy and stone extraction by standard techniques (extraction balloon or Dormia basket) were included in this study. Results: A total of 1080 ERCPs were performed to extract biliary duct stones. The mean age was 58.9 +/- 14.4 years and 59.5% were females. The mean diameter of the Bile duct was 13.4+/- 4.31 mm. The presence of a biliary stricture in 6.3%. The primary vacuity rate was 75.1%. Supplementary techniques were used in 22.7% of cases. On multivariate analysis, only the presence of cholangitis (OR:1.9 CI95%: 0.2-1 p=0.001), impacted and/or large stone (OR:2.5 CI95%:0.5-1.3 p<0.001), dilatation of the CBD >15mm (OR:0.88 CI95%: -0.17- -0.07 p<0.001), and biliary stricture (OR:2.9 CI95%:0.4-1.7 p=0.002) were significantly associated with failure of the primary CBD vacuity rate. The overall vacuity rate after using the supplementary techniques was 92.4%. Conclusion: In our study, predictive factors for failure of the primary CBD vacuity rate were the presence of cholangitis, impacted and/or large stone, dilatation of the CBD (>15mm) and biliary stricture.