To evaluate the efficacy and safety of endoscopic sphincterotomy (EST) + endoscopic papillary large balloon dilation (EPLBD) vs isolated EST. We conducted a retrospective single center study over two years, from February 2010 to January 2012. Patients with large (≥ 10 mm), single or multiple bile duct stones (BDS), submitted to endoscopic retrograde cholangio-pancreatography (ERCP) were included. Patients in Group A underwent papillary large balloon dilation after limited sphincterotomy (EST+EPLBD), using a through-the-scope balloon catheter gradually inflated to 12-18 mm according to the size of the largest stone and the maximal diameter of the distal bile duct on the cholangiogram. Patients in Group B (control group) underwent isolated sphincterotomy. Stones were removed using a retrieval balloon catheter and/or a dormia basket. When necessary, mechanical lithotripsy was performed. Complete clearance of the bile duct was documented with a balloon catheter cholangiogram at the end of the procedure. In case of residual lithiasis, a double pigtail plastic stent was placed and a second ERCP was planned within 4-6 wk. Some patients were sent for extracorporeal lithotripsy prior to subsequent ERCP. Outcomes of EST+EPLBD (Group A) vs isolated EST (Group B) were compared regarding efficacy (complete stone clearance, number of therapeutic sessions, mechanical and/or extracorporeal lithotripsy, biliary stent placement) and safety (frequency, type and grade of complications). Statistical analysis was performed using χ(2) or Fisher's exact tests for the analysis of categorical parameters and Student's t test for continuous variables. A P-value of less than 0.05 was considered statistically significant. One hundred and eleven patients were included, 68 (61.3%) in Group A and 43 (38.7%) in Group B. The mean diameter of the stones was similar in the two groups (16.8 ± 4.4 and 16.0 ± 6.7 in Groups A and B, respectively). Forty-eight (70.6%) patients in Group A and 21 (48.8%) in Group B had multiple BDS (P = 0.005). Overall, balloon dilation was performed up to 12 mm in 10 (14.7%) patients, 13.5 mm in 17 (25.0%), 15 mm in 33 (48.6%), 16.5 mm in 2 (2.9%) and 18 mm in 6 (8.8%) patients, taking into account the diameter of the largest stone and that of the bile duct. Complete stone clearance was achieved in sixty-five (95.6%) patients in Group A vs 30 (69.8%) patients in Group B, and was attained within the first therapeutic session in 82.4% of patients in Group A vs 44.2% in Group B (P < 0.001). Patients submitted to EST+EPLBD underwent fewer therapeutic sessions (1.1 ± 0.3 vs 1.8 ± 1.1, P < 0.001), and fewer required mechanical (14.7% vs 37.2%, P = 0.007) or extracorporeal (0 vs 18.6%, P < 0.001) lithotripsy, as well as biliary stenting (17.6% vs 60.5%, P < 0.001). The rate of complications was not significantly different between the two groups. EST+EPLBD is a safe and effective technique for treatment of difficult BDS, leading to high rates of complete stone clearance and reducing the need for lithotripsy and biliary stenting.