Duodenal diverticulum (DD) is a common incidental finding, which rarely causes complications. Perforation is one of the most feared and the least common complications. Surgery is the mainstay for complicated duodenal diverticulum, but with the advancement of medical treatment and intensive care, nonoperative management has been reported. We present a rare case of perforated DD that failed medical management and subsequently underwent surgical intervention. A 77-year-old, healthy female presented with right-sided abdominal pain with low-grade fever and leukocytosis. Computed tomography (CT) of the abdomen showed retroperitoneal fluid collection around the second part of the duodenum, which was not amenable to percutaneous drainage. Contrast studies showed no evidence of perforation or leak of the stomach or duodenum. The diagnosis was made via an upper endoscopy that showed a large periampullary duodenal diverticulum with purulent drainage and normal-looking ampulla. After failed conservative management with broad-spectrum antibiotics and worsening symptoms, she underwent excision and primary repair of the diverticulum with a jejunal serosal patch and exploration of the common bile duct (CBD). She had an uncomplicated postoperative course and was discharged home on postoperative day four. Although rare, the duodenal diverticular perforation can be a life-threatening complication. Combined subjective, clinical, and radiological assessment of the patient is crucial in deciding whether to operate or not.