Objectives: Two-stage treatment of common bile duct stones by Endoscopic Retrograde Cholangio-Pancreatography and subsequent laparoscopic cholecystectomy is well established. In many cases multiple procedures are needed before clearance of the common bile duct is obtained. This study aimed to describe the clinical course from common bile duct stone diagnosis to successful clearance. Materials and Methods: A prospective observational study from 2011 to 2014 of consecutive patients diagnosed with common bile duct stones undergoing Endoscopic Retrograde Cholangio-Pancreatography at a public university hospital. Results: In this study 297 patients with common bile duct stones were identified. More than one Endoscopic Retrograde Cholangio-Pancreatography was performed in 174 (59%) patients and more than two in 51(17%) before clearance. A sphincterotomy was performed in 269 (91%) patients and 189 (64%) had a stent inserted. Bleeding occurred in 17 (6%) requiring injection treatment and post procedure complications occurred in 38 (13%). Subsequent laparoscopic cholecystectomy was performed in 180 (61%) patients. Overall, the patients were hospitalized for 11 (8.5) days and the length of treatment from diagnose to stone clearance was 49 (84.5) days. Overweight, pancreatitis at admission, universal anesthesia, and expert level endoscopist inversely determined common bile duct clearance failure. Conclusions: Common bile duct clearance by Endoscopic Retrograde Cholangio-Pancreatography requires multiple procedures and complications are frequent leading to prolonged treatment and hospitalization suggesting a limited efficacy.