Whole-body-enhanced computed tomography of a septuagenarian woman hit by a truck revealed a traumatic aortic dissection (Stanford B) and arterial bleeding from the right lumbar artery in the right iliopsoas muscle. Angiography revealed an active arterial extravasation from a false lumen of the left lumbar artery. We performed a transcatheter arterial embolization (TAE) of the right lumbar artery. After fenestration of the intimal flap, the left lumbar artery was successfully selected and embolized; the patient's clinical condition subsequently stabilized. This is the first report of successful treatment of a lumbar artery injury with a traumatic aortic dissection by a TAE.