Introduction: Diverticulitis is a well described inflammatory condition of the wall of the gastrointestinal tract with an overall prevalence of 2-10% in developing countries. Typically, the descending and sigmoid colon are affected more commonly than the ascending colon and small bowel in the Western population. Diverticula of the distal ileum are particularly uncommon, with a reported rate of 0.06-1.3% (Jeong et al. 2014). Due to difficulty in pre-operative diagnosis, there is no consensus on therapeutic strategy for right-sided diverticulitis (Lee et al. 2010). Here, the authors present a case of non-Meckel’s diverticulitis of the distal ileum in a Caucasian U.K. patient. Case description: A 63 year old man presented to the Emergency Department with a one day history of abdominal distension, periumbilical pain radiating to the right iliac fossa, nausea and sweats. He had not defecated for 2 days but reported passing flatus. Past medical history included gout, rheumatoid arthritis and Ulcerative Colitis, managed with Sulfasalazine. He was not a smoker. On examination, abdomen was visibly distended. There was maximal tenderness in the lower central abdomen and guarding to palpation. Digital rectal examination was normal. Chest radiograph was unremarkable. Plain abdominal film showed faecal loading of the colon, but no obstructive features. C-Reactive Protein (CRP), amylase and white cell count on admission were normal. On repeat testing, CRP was 208mg/L, white cell count 10x109/L, venous lactate 2.3mmol/L and haemoglobin 13.1g/L. Intravenous fluids and broad spectrum antibiotics were commenced. CT imaging was arranged in view of the severity of symptoms, biochemical findings, patient’s age, medication and history of colitis. CT abdomen pelvis with oral contrast showed a severely inflamed ileal diverticulum. There was no suggestion of a diverticulum on previous radiological or endoscopic investigations. The patient proceeded to surgery for open resection of perforated diverticulum (39cm of ileum) and small bowel anastomosis. Results and Conclusions: After 24 hour High Dependency observation, the patient made an uneventful recovery. Histological analysis confirmed a thin-walled, diffusely ulcerated, perforated ileal diverticulum resulting from obstructing food. Anatomically, diverticula are characterised by herniation of mucosa and submucosa through the muscular bowel wall and a true diverticulum should involve all layers. Diverticula of the small bowel are more commonly proximal (75% jejunal, versus 5% ileal). The position, conversely to a Meckel’s diverticulum, is usually on the mesenteric side of the bowel. The aetiology of jejuneo-ileal diverticula is not fully understood however focal muscular weakness, motility dysfunction, high segmental intraluminal pressure and biogenetic factors are believed to contribute (Nakatani et al. 2016). There is close clinical and biochemical overlap between a presentation of appendicitis and right sided diverticulitis. However, previous studies have suggested subtle clinical variations to aid their distinction, such as duration of onset, location or migration of pain and severity of systemic response (Lee et al. 2010). The use of ultrasonography and CT to aid diagnosis has been advocated, which may show bowel wall thickening, peri-colonic fat infiltration, extra-luminal air or abscess. Compared to duodenal, small bowel diverticula are almost 4 times more likely to perforate (Nakatani et al. 2016). Take home message: Although less common than appendicitis, diverticulitis of the ascending colon or terminal ileum should be considered in patients presenting with right iliac fossa pain. Limited small bowel resection and anastomosis or diverticulectomy is a safe surgical method to use in some cases of ileal diverticulitis. Many cases of uncomplicated small bowel diverticulitis may be treated conservatively without requiring operative intervention. Thus accurate and early diagnosis, aided by radiological imaging can ensure appropriate clinical management and avoid unnecessary surgery and its associated risks for patients presenting with acute, uncomplicated small bowel diverticulitis.