Duodenal diverticulitis is a rare complication of the duodenal diverticulum. Its rarity is due to the relatively large diameter of the duodenum, which makes the intraluminal flow of sterile liquid duodenal contents fluent. Additionally, nonspecific signs and symptoms of duodenal diverticulitis make it very difficult to diagnose properly. We describe a patient presenting with abdominal pain, nausea, and leukocytosis, with diverticulitis of the third portion of the duodenum caused by the impaction of a foreign body, who was diagnosed and treated with enteroscopy.