Isolated inflammatory aneurysm of the common iliac artery is a rare condition. Previously reported cases presented with urologic complications owing to entrapment of the ureter in the perianeurysmal fibrosis. We report a case of a healthy young man who presented with acute abdominal pain in the right lower quadrant without urologic complications mimicking acute appendicitis. The pain was caused by an isolated inflammatory aneurysm of the right common iliac artery measuring 4 cm in diameter. Three years after open aneurysmal resection and graft interposition, the patient is doing well, with excellent peripheral circulation. The available literature on presentation, diagnosis, and treatment is reviewed.