This report describes the need for a tailored approach for intracranial vascular occlusive disease and introduces the usefulness of the OA as a donor artery for interposition graft.A 65-year-old male patient suffered from repeated transient ischemic attack (TIA). Imaging studies revealed complete occlusion of the proximal left side of the internal carotid artery (ICA) and multiple infarction in the watershed zone. We planned superficial temporal artery-middle cerebral artery (STA-MCA) bypass to restore cerebral blood flow and to prevent the progression of infarction. However, the parietal branch of the STA was too small in diameter and not suitable as a single donor for the bypass in order to supply sufficient blood flow. Moreover, the frontal branch of the STA had collateral channels through the periorbital anastomosis into the cerebral cortex that could result in infarction during clamping for anastomosis.We determined that tailored treatment planning was necessary for successful revascularization under these conditions. Thus, we performed a bypass between the parietal branch of the STA and a cortical branch of the MCA as an "insurance bypass." Then we performed another bypass between the frontal branch of the STA and a cortical branch of the MCA using an ipsilateral occipital artery (OA) interposition graft. The patient had no perioperative complications, and postoperative imaging confirmed the restoration of cerebral blood flow.When end-to-side anastomosis in single-branch bypass is not appropriate for cerebral revascularization, a tailored double-barrel "insurance bypass" with an OA interposed graft could be a good alternative treatment modality. In addition, an OA interposition graft is a useful option for double-barrel bypass surgery in such cases of intracranial vascular occlusive disease.