An 83-year-old woman, diagnosed as having cholelithiasis, was admitted to the Department of Surgery, Nippon Medical School, with right hypochondrial pain. Ultrasonography and computed tomography revealed a mass in the gallbladder fundus and a hypovascular tumor in the anterior segment of the liver. Magnetic resonance imaging showed stenosis of the intrahepatic bile duct and dilatation of its proximal portion. She was diagnosed as having intrahepatic bile duct carcinoma combined with gallbladder carcinoma. At laparotomy, there was evidence of multiple peritoneal metastases and intraoperative histological examination of the gallbladder tumor revealed adenocarcinoma. Accordingly, only cholecystectomy and needle biopsy of the liver tumor was performed. Histological examination of the gallbladder revealed papillary adenocarcinoma invading the muscularis propria with medullary growth or intermediate stroma. There was no microvessel invasion, no perineural invasion and no lymph node involvement. On the other hand, the liver tumor was a cholangiocarcinoma with a well-differentiated tubular pattern. Therefore, this was a rare case of synchronous carcinoma of the gallbladder associated with intrahepatic bile duct carcinoma.