OBJECTIVE AND IMPORTANCEThe vasa vasorum are involved in the pathophysiological development of carotid artery atherosclerosis, providing vascular support to the thickened intima and plaque. When advanced atherosclerosis causes carotid artery occlusion, the vasa vasorum may serve as a means of revascularization.CLINICAL PRESENTATIONWe studied four patients with internal carotid artery occlusion who exhibited revascularization, distal to the occlusion, by small vascular channels that were inconsistent with recanalization through the thrombus. The channels had an angiographic appearance consistent with their being hypertrophied vasa vasorum. Significant collateral circulation was provided by the revascularization.INTERVENTIONAll four patients exhibited adequate collateral circulation and were treated with antiplatelet or anticoagulation medication.CONCLUSIONThe vasa vasorum have not been previously reported to contribute to the revascularization of occluded arteries. The four cases presented in this report suggest that the vasa vasorum can be a source of collateral circulation after carotid artery occlusion secondary to atherosclerotic disease.