Gallbladder duplication is a rare congenital anomaly which is important in clinical practice because it may cause some clinical, surgical, and diagnostic problems. We present a case of duplicated gallbladder diagnosed and treated during laparoscopy. There was no sign in preoperative workup about the duplication. Ultrasonography revealed multiple stones in gallbladder and laparoscopic cholecystectomy was planned. Gallbladder duplication was detected during the operation and successfully treated by laparoscopy. This case illustrates the need for complete removal of both gallbladders during initial surgery. Precise intraoperative recognition of vascular and biliary anatomy-including abnormalities-is necessary to avoid mistakes during surgery.