Bilateral lower extremity blood flow determinations were made in experimental animals before and after cross-over grafting operations. The effect of the graft was to double the flow through the new afferent parent artery rather than to “steal” blood from the peripheral bed of the artery from which the graft originated. An arteriovenous fistula on the side to which the graft extended caused as much as a tenfold increase in graft flow without “stealing” from the contralateral extremity. Flow measurements before and after a common carotid-subclavian artery bypass operation in a patient with proximal subclavian occlusion demonstrated that this shunt does not decrease blood flow of the peripheral common carotid artery.