Acute lower back pain is a common chief complaint in emergency departments. Rupture of an abdominal aortic aneurysm causing sudden onset of lower back pain with recurrent attacks may mislead emergency department physicians to a diagnosis of renal colic or myalgia. We report on a case of a 75-year-old female presenting with recurrent lower back pain which turned out to be a rupture of an abdominal aortic aneurysm. Because intermittent pain was accompanied by shock, an acute abdominal condition was suspected. Rupture of an abdominal aortic aneurysm was diagnosed by ultrasound and confirmed by computed tomography. She underwent an emergency operation and recovered uneventfully. It is recommended that a more-detailed and thorough evaluation of lower back pain is mandatory. Recurrent lower back pain is usually related to renal colic and myalgia; rupture of an abdominal aortic aneurysm with such clinical presentation may be easily misdiagnosed, which could result in devastating consequences.