AIM: To analyze the efficacy of routine intraoperative ultrasound (IOUS) as a guide for understanding biliary tract anatomy, to avoid bile duct injury (BDI) after laparoscopic cholecystectomy (LC), as well as any burden during the learning period.METHODS: A retrospective analysis was performed using 644 consecutive patients who underwent LC from 1991 to 2006. An educational program with the use of IOUS as an operative guide has been used in 276 cases since 1998.RESULTS: IOUS was highly feasible even in patients with high-grade cholecystitis. No BDI was observed after the introduction of the educational program, despite 72% of operations being performed by inexperienced surgeons. Incidences of other morbidity, mortality,and late complications were comparable before and after the introduction of routine IOUS. However, the operation time was significantly extended after the educational program began (P < 0.001), and the grade of laparoscopic cholecystitis (P = 0.002), use of IOUS (P = 0.01), and the experience of the surgeons (P=0.05) were significant factors for extending the length of operation.CONCLUSION: IOUS during LC was found to be a highly feasible modality, which provided accurate, realtime information about the biliary structures. The educational program using IOUS is expected to minimize the incidence of BDI following LC, especially when performed by less-skilled surgeons.