Introduction: Missing a leaking abdominal aortic aneurysm (AAA) is common in medical practice because few at-risk patients have a history of AAA and many have an unusual presentation. Background: AAA is less common among Asians than white Caucasians of the same age. Our patient had no significant risk factors apart from age and sex and had an unusual presentation. Patient and Methods: A 67-year-old Asian man presented to the emergency room (ER) with a 1-day history of nausea, vomiting, diarrhoea, fever and abdominal pain. He was febrile, dehydrated. and had marked tenderness at the right iliac fossa. Laboratory findings suggested bacterial gastroenteritis but this did not explain the localized tenderness at the right iliac fossa. Result and Discussion: A CT scan of the abdomen revealed an AAA arising above the origins of the renal arteries, an intramural thrombus, a retroperitoneal haematoma and a leak extending to the right iliac fossa. The patient was transferred to another hospital and underwent exploratory laparotomy, surgical repair of the aneurysm, and aortobi-iliac grafting with removal of the thrombus. The patient was discharged in good shape 3 weeks after surgery. Without the CT scan of the abdomen, the AAA could have been missed and the patient treated for severe gastroenteritis.