Biliary obstruction may result from benign or malignant strictures of the bile ducts,1gallstones within the biliary tree,2or extrinsic biliary compression such as swelling of the pancreas.2,3In 1948, P. L. Mirizzi4described an unusual cause of biliary obstruction secondary to extrinsic compression of the common bile duct in patients with chronic cholecystitis. Mirizzi syndrome has since been redefined to encompass a spectrum of acquired biliary anomalies, which also include cholecystocholedochal fistulas.3,5In type I Mirizzi syndrome, the cystic duct lies parallel to the hepatic or common bile duct, and an impacted gallstone in the cystic duct or neck of the gallbladder leads to intermittent obstruction of the bile duct (Figure 2). Chronic inflammation and compression from cholecystitis may result in the development of a cholecystocholedochal fistula (Mirizzi type II to IV) (Figure 2).2,3Intraoperative cholangiography aids in avoiding common bile duct injury in the often severely inflamed porta hepatis associated with Mirizzi syndrome.1Patients with more advanced disease frequently require a choledochojejunostomy or hepaticojejunostomy because lateral repair of the common bile duct with a T tube may result in biliary stricture. A select group of small type II biliary fistulas have been successfully managed with choledochoplasty by using a cuff of gallbladder remnant. Mirizzi syndrome occurs in fewer than 1% of patients with cholelithiasis undergoing cholecystectomy.1,3Nevertheless, it should always be considered in the differential diagnosis of obstructive jaundice, especially in patients with an unclear cause of disease.