Background and study aims: Extraction of common bile duct stones at endoscopic retrograde cholangiopancreatography can be technically challenging when the size of the stone exceeds that of an endoscopic sphincterotomy. The aim of this study was to evaluate the efficacy and safety of papillary balloon dilation after sphincterotomy for extraction of these difficult-to-remove bile duct stones. Patients and methods: This was a prospective study of all patients with large common bile duct stones that could not be extracted using a stone retrieval balloon and basket after endoscopic sphincterotomy. These patients underwent papillary dilation using a radial expansion balloon after maximum sphincterotomy. Biliary ductal clearance was then reattempted using a stone retrieval balloon and/or basket. The success rate and the complication rate for the papillary balloon dilation technique were assessed. Results: A total of 60 patients (16 men, 44 women; mean age 58, range 28 - 73) were enrolled in this study. The mean stone size was 16 mm (range 12 - 20 mm). After maximum sphincterotomy and papillary balloon dilation, ductal clearance was achieved in 57/60 patients (95 %); three patients required adjunctive mechanical lithotripsy for stone extraction. Bleeding occurred in five patients (8.3 %) and was managed conservatively in all cases. Conclusions: Papillary balloon dilation after endoscopic sphincterotomy is an effective and safe technique for retrieval of difficult common bile duct stones. The procedure is technically safe and obviates the need for mechanical lithotripsy in a majority of patients.