Objective: The overlay of virtual images on the surgical field, defined as augmented reality, has been used for image-guidance during various neurosurgical procedures. Although this technology could conceivably address certain inherent problems of extracranial-to-intracranial bypass procedures, this potential has not been explored to date. We evaluate the usefulness of an augmented reality-based setup, which could help in harvesting donor vessels through their precise localization in real-time, in performing tailored craniotomies, and in identifying preoperatively selected recipient vessels for the purpose of anastomosis. Methods: Our method was applied to three patients suffering from Moya-Moya disease who underwent superficial temporal artery-to-middle cerebral artery anastomoses, and to one patient who underwent an occipital artery-to-posteroinferior cerebellar artery bypass due to a dissecting aneurysm of the vertebral artery. Patients' heads, skulls and extracranial and intracranial vessels were preoperatively segmented from 3-dimensional image data sets (3-dimensional digital subtraction angiography, angio-magnetic resonance imaging, angio-computed tomography), and injected intraoperatively into the operating microscope's eyepiece for image guidance. Results: In each case, the described setup helped in precisely localizing donor and recipient vessels, and in tailoring craniotomies to the injected images. Conclusions: The presented system based on augmented reality can optimize the workflow of extracranial-to-intracranial bypass procedures, by providing essential anatomical information, entirely integrated to the surgical field, and can help to perform minimally invasive procedures.