Intraductal papillary mucinous neoplasm (IPMN) involving the biliary system is rare. To date, only a few cases of IPMN arising from the extrahepatic bile duct have been reported. In our case, extrahepatic IPMN arose in the remnant cystic duct after cholecystectomy, and to the best of our knowledge, this is the first report in the remnant cystic duct after cholecystectomy. A 74-year-old woman was referred for right upper quadrant pain lasting one day. Ultrasonography (US) showed a lobulated and hyperechoic mass with an outer linear hypoechoic lesion located adjacent to the dilated common bile duct. Contrast enhanced computed tomography showed a heterogeneously enhancing mass. Magnetic resonance imaging (MRI) showed a heterogenous mass with an outer semicircular high signal portion indicating remnant cystic duct.