US is becoming a widely used diagnostic and therapeutic tool in emergency medicine training and practice. Its use in detecting an AAA is efficient and practical and can occur concurrently with resuscitation. US of the abdominal aorta has been shown to be highly accurate for the detection of AAA and to decrease the time to operative repair of ruptured AAA. The emergency physician should consider using US to search for an AAA in any patient presenting with abdominal or back pain or with shock of unknown etiology.