A case of delayed presentation of a traumatic false aneurysm in the left arm 50 years after penetrating injury sustained during World War II is described. The original injury resulted in brachial artery occlusion and complete median nerve palsy. The false aneurysm presented with a spontaneous, contained rupture. Surgical repair was performed after duplex ultrasound localization of the lesion to a small collateral artery lateral to the elbow, thereby avoiding dissection in the densely scarred tissue plains in the antecubital fossa. Duplex ultrasound was also used intraoperatively to facilitate localization of the aneurysm neck and to confirm absence of flow in the sac after repair. A brief historical review of traumatic false aneurysms caused by combat injuries, is provided. The progress in the treatment of such injuries gained by wartime experience is reviewed.