Three patients with subsequently proven small-bowel diverticulitis were studied with preoperative CT. In all three cases, an inflammatory mass was present, two involving the terminal ileum and cecum and one involving the jejunum. While the findings in the two cases of ileal diverticulitis simulated appendicitis, in the case of jejunal diverticulitis the diagnosis was suggested on the basis of CT findings. Small-bowel diverticulitis should be included in the differential diagnosis if an inflammatory mass involving the small bowel is demonstrated on CT.