The patient was a 61-year-old female. The patient was seen in Tongji Hospital affiliated to Tongji Medical College of Huazhong University of Science and Technology on August 23, 2018 due to distension and pain in the right upper abdomen. Abdominal CT showed that the gallbladder was slightly enlarged, nodular high-density shadows were seen in the gallbladder, and the gallbladder wall was slightly thickened. Diagnostic opinion: gallstones and cholecystitis. The patient refused surgery, and the symptoms were relieved after conservative treatment. Half a month later, he appeared again with distension and pain in the right upper abdomen and was admitted to our hospital. Physical examination: No yellowing staining of the skin and sclera, flat and soft abdomen, tenderness in the right upper abdomen, no rebound pain, and negative Murphy sign. There were no obvious abnormalities in blood routine, liver and kidney function and chest radiographs. Abdominal color Doppler ultrasound showed that the size of the gallbladder section was normal, the wall was not smooth, and strong echoic light clusters could be seen in the gallbladder cavity, followed by acoustic shadows. In order to further determine whether there are stones in the intrahepatic and extrahepatic bile ducts, MRCP examination was performed. MRCP showed that there was no stenosis, obstruction and dilation in the intrahepatic and extrahepatic bile ducts. See double gallbladder (Figure 1,Figure 2), the wall is thick, and stones can be seen in the cavity of both gallbladders. To improve the perioperative preparation, the patient underwent laparoscopic cholecystectomy (LC) on September 18, 2018. Intraoperative exploration showed that the cystic duct opened in the right wall of the common bile duct, and the cystic duct and gallbladder artery were separated and clipped and severed. When the ampulla of the gallbladder was continued to be separated to the hilar, a cystic deformity was seen. Combined with the preoperative MRCP results, it was considered as a mutant "small gallbladder" (Figure 3,Figure 4), it was confirmed that there were double gallbladders during the operation, and the two gallbladders had their own cystic ducts communicating with the common bile duct respectively. The two gallbladders were densely connected and wrapped by connective tissue. Postoperatively, the "large gallbladder" was about 8 cm ×2 cm in size, containing yellow-brown bile, and a brown stone with a diameter of about 2 cm ×1 cm was found in the cavity. The "small gallbladder" was about 2 cm ×1 cm in size, without obvious bile, and the cavity was a filled white small stone with a diameter of about 0.2 cm (Figure 5,Figure 6)。 He was discharged 8 days after surgery. Pathology: Under light microscope, inflammatory cell infiltration was seen in the wall of the larger gallbladder and the smaller gallbladder, and stones were seen in the cystic cavity (Figure 7,Figure 8), diagnosis: (1) cholecystolithiasis; (2) Chronic cholecystitis.