AIM To examine the influence of night duty(ND) on endoscopic therapy for biliary duct stones.METHODS The subjects consisted of 133 patients who received initial endoscopic therapy for biliary duct stones performed by eight endoscopists after they had been on(ND group, n = 34 patients) or not [day duty(DD) group, n = 99 patients]. Patient characteristics(age, gender, history of abdominal surgery, transverse diameter of the largest stone, number of stones), years of experience of the endoscopists, endoscopic procedures [sphincterotomy, papillary balloon dilation(EPBD), papillary large balloon dilation(EPLBD)], and outcomes of initial endoscopy(procedure time; rate of stone removal by the first endoscopist; proceduresuccess rate by the first endoscopist: removal of stones or endoscopic retrograde biliary drainage; rate of final stone removal; final procedure success rate; complications; hospitalization after the procedure) were compared retrospectively between the two groups. History of abdominal surgery and treatment outcomes were also compared between the groups for each of the four endoscopists who performed most of the procedures in the ND group.RESULTS There were no significant differences regarding the number of treatments performed by each endoscopist or the years of experience between the ND and DD groups. The frequency of endoscopic retrograde cholangiopancreatography procedures did not differ significantly between the groups. There were also no significant differences regarding patient characteristics: age, gender, history of abdominal surgery(ND 7: Billroth II 4, R-Y 3; DD 18: double tract reconstruction 1, Billroth I 3, Billroth II 6, R-Y 7, duodenoduodenostomy for annular pancreas 1), transverse diameter of largest stone, and number of stones between the two groups. Among the treatment procedures, the endoscopic s p h i n c t e r o t o m y a n d E P B D r a t e s d i d n o t d i f f e r significantly between the groups. However, EPLBD was performed more frequently in the ND group [47.1%(16/34) v s 19.2%(19/99)]. Regarding outcomes, there were no significant differences in the rate of stone removal, procedure success rate, complications(ND: pancreatitis 1; DD: pancreatitis 6, duodenal bleeding 1, decreased blood pressure 1, hypoxia 2), or hospitalization after the procedure. However, the procedure time was significantly longer in the ND group(71.5 ± 44.7 vs 54.2 ± 28.8). Among the four endoscopists, there were no significant differences in patient history of abdominal surgery, removal of stones, or procedure success rate. However, the procedure time for one endoscopist was significantly longer in the ND group.CONCLUSION The time required for endoscopic therapy for bile duct stones might be influenced by ND. AIM To examine the influence of night duty (ND) on endoscopic therapy for biliary duct stones. METHODS The subjects consisted of 133 patients who received initial endoscopic therapy for biliary duct stones performed by eight endoscopists after they had been on (ND group, n = 34 patients) or not [day duty (DD) group, n = 99 patients]. Patient characteristics (age, gender, history of abdominal surgery, transverse diameter of the largest stone, number of stones), years of experience of the endoscopists, endoscopic procedures [sphincterotomy, papillary balloon dilation (EPBD), papillary large balloon dilation (EPLBD)], and outcomes of initial endoscopy (procedure time; rate of stone removal by the first endoscopist; procedures uccess rate by the first endoscopist: removal of stones or endoscopic retrograde biliary drainage; rate of final stone removal; final procedure success rate; complications; hospitalization after the procedure) were compared retrospectively between the two groups. History of a bdominal surgery and treatment outcomes were also also compared between the groups for each of the four endoscopists who performed most of the procedures in the ND group. RESULTS There were no significant differences regarding the number of treatments performed by each endoscopist or the years of experience between the ND and DD groups. The frequency of endoscopic retrograde cholangiopancreatography procedures did not differ significantly between the groups. There were also no significant differences regarding patient characteristics: age, gender, history of abdominal surgery (ND 7: Billroth II 4, RY 3; DD 18: double tract reconstruction 1, Billroth I 3, Billroth II 6, RY 7, duodenoduodenostomy for annular pancreas 1), transverse diameter of largest stone, and number of stones between the two groups. Among the treatment procedures, the endoscopic sphincterotomy and EPBD ratesdidnotdiffer significantly between the groups. However, EPLBD was performed more frGiven outcomes, there were no significant differences in the rate of stone removal, procedure success rate, complications (ND: pancreatitis 1; DD : pancreatitis 6, duodenal bleeding 1, decreased blood pressure 1, hypoxia 2), or hospitalization after the procedure. However, the procedure time was significantly longer in the ND group (71.5 ± 44.7 vs 54.2 ± 28.8). Among the four endoscopists, there are no significant differences in patient history of abdominal surgery, removal of stones, or procedure success rate. However, the procedure time for one endoscopist was significantly longer in the ND group. CONCLUSION The time required for endoscopic therapy for bile duct stones might be influenced by ND.