Ascending cholangitis is a clinical syndrome characterized by fever, jaundice, and abdominal pain. It is caused by stasis and infection in the biliary tract with severity ranging from mild to life threatening. The most frequent causes of biliary obstruction and ascending cholangitis are choledocholithiasis, benign biliary stricture, and obstructing malignancy. In this report, we describe a rare case of a large periampullary duodenal diverticulum impacted with a food bezoar, causing pancreaticobiliary obstruction and ascending cholangitis.