they are usually asymptomatic, several complications have been reported. A 78-year-old man was admitted to our hospital with high-grade fever (39.6°C) and jaundice. His laboratory data showed liver dysfunction and elevations of the white blood cell count and serum C-reactive protein concentration. Abdominal ultrasonography demonstrated dilated biliary ducts. Abdominal computed tomography (CT) revealed a diverticulum in the second part of the duodenum (● Fig. 1). We suspected obstructive cholangitis. Endoscopic retrograde cholangiography (ERC) was performed. Gastrointestinal endoscopy revealed a periampullary diverticulum occupied by a yellow stone (● Fig. 2). ERC showed no abnormalities (● Fig. 3). Therefore, we made a diagnosis of biliary tract obstruction caused by an enterolith in the periampullary duodenal diverticulum. We performed successful endoscopic removal of the enterolith (● Fig. 4). The extracted enterolith was oval-shaped, yellowish in color, measured approximately 3 cm in diameter, and had a hard outer rim with an irregular surface (● Fig. 5). Separate layers within the wall were appreciated and there was no evidence of any nidus, such as a fruit pit. Infrared absorption spectrophotometry showed that the enterolith consisted mainly of deoxycholic acid (● Fig. 6). Duodenal diverticula are commonly encountered and are generally regarded as clinically insignificant entities. They can, however, sometimes produce serious complications, including diverticulitis, perforation, hemorrhage, biliary and/or pancreatic obstruction, partial duodenal obstruction, fistula formation with adjacent organs, diarrhea secondary to blind loop syndrome, and enterolith formation [1]. Enterolith formation is known to occur within regions of stasis, such as Meckel’s diverticulum or a blind loop, or as a result of stricture due to Crohn’s disease or tuberculosis. Duodenal diverticula may also represent such a region of stasis [2]. In conclusion, we performed successful endoscopic removal of an enterolith in a duodenal diverticulum. Obstructive cholangitis caused by an enterolith in a periampullary diverticulum is rare, but is an important entity for endoscopists.