A 66-year-old man was admitted for an early cancer in the gastric corpus. At laparotomy, the gallbladder was located on the left side of the round ligament and attached to the lateral segment of the liver. This finding was compatible with a left-sided gallbladder. Postoperative ultrasonograms and portograms demonstrated anomalies of the intrahepatic portal vein as follows; The left umbilical portion and the posterior point of the portal branch were lacking. The posterior point was seen as an umbilical portion. An endoscopic retrograde cholangiopancreaticogram showed the cystic duct entering into the right side of the common bile duct confluent to the accessory pancreatic duct. A left-sided gallbladder unassociated with visceral inversion is a rare congenital anomaly. Forty-one cases have been reported in Japan, five with anomalies of the intrahepatic portal vein and two with anomalous junction of the pancreaticobiliary ductal system. To our knowledge, our patient is the only case of the left-sided gallbladder which both congenital anomalies.