Report of a case of major anomaly of the primitive digestive tube. Due to gastric malrotation the stomach was located to the right, behind the right lobe of the liver and the duodenum ran upward and to the left, passing behind the major biliary tract (mirror image of the normal gastroduodenal structure). The small intestine having undergone a normal rotation, the splenic flexure did not exist, while the ileum and colon gave an image of inversed "Mesenterium commune" (absence of the transverse colon, the ascending colon to the right and all the small intestine reassembled to the left). The patient, who presented with a choledocholithiasis underwent an Oddian sphincterotomy in an unusual position.