Background/Aims: Endoscopic transpapillary gallbladder drainage (ETGBD) is useful for the treatment of acute cholecystitis; however, the technique is difficult to perform. When intraductal ultrasonography (IDUS) is combined with ETGBD, the orifice of the cystic duct in the common bile duct may be more easily detected in the cannulation procedure. The aim of this study was to evaluate the efficacy of ETGBD with IDUS compared with that of ETGBD alone. Methods: A total of 100 consecutive patients with acute cholecystitis requiring ETGBD were retrospectively recruited. The first 50 consecutive patients were treated using ETGBD without IDUS, and the next 50 patients were treated using ETGBD with IDUS. Through propensity score matching analysis, we compared the clinical outcomes between the groups. The primary outcome was the technical success rate. Results: The technical success rate of ETGBD with IDUS was significantly higher than that of ETGBD without IDUS (92.0% vs. 76.0%, p=0.044). There was no significant difference in procedure length between the two groups (74.0 min vs. 66.7 min, p=0.310). The complication rate of ETGBD with IDUS was significantly higher than that of ETGBD without IDUS (6.0% vs. 0%, p<0.001); however, only one case showed an IDUS technique-related complication (pancreatitis). Conclusions The assistance of IDUS may be useful in ETGBD.