The authors present a case of midgut perforated diverticulitis in a 78-year-old patient, associated with a colovesical fistula and sigmoid obstruction of diverticular origin. Surgical resection of the small bowel segment affected together with primary anastomosis is the preferred treatment in patients with symptomatic complicated jejunoileal diverticular disease. In complicated midgut diverticulitis the preoperative diagnosis is a challenge: the symptoms are aspecific and imaging techniques are of no use. As a result, the diagnosis of complicated jejunoileal diverticulitis can be quite difficult, and a definitive diagnosis may often be made only after surgical exploration.