A 24-year-old lady with recurrent upper abdominal pain, underwent surgery for cholelithiasis based on imaging diagnosis by ultrasound scanning. At laparotomy, the gall bladder could not be found either in its normal or ectopic locations. The diagnosis of agenesis of the gall bladder was confirmed by operative cholangiography. Duplication cysts of the hepatic flexure were discovered in the position normally occupied by the gall bladder. The stony hard faeces in the cysts were probably interpreted as gallstones on ultrasound. This rare condition is discussed and the importance of intraoperative cholangiography is stressed.