We evaluated the feasibility of using Split-dose iodine-123-IMP SPECT for identifying the hemodynamic status in patients with bilateral carotid artery occlusive diseases. We studied 8 patients with angiographically-confirmed bilateral severe occlusive lesions (occlusion or >70% stenosis) in the cervical carotid artery. Of these patients, we performed carotid artery stenting (CAS) for carotid artery stenosis in 4 patients with contralateral carotid occlusion and for the symptomatic side in 1 patient with bilateral carotid stenosis. The remaining 3 patients were medically treated. The rest regional cerebral blood flow (rCBF) and cerebrovascular reactivity (CVR) were quantitatively evaluated twice by the split dose method before and after CAS. CAS for 1 side in patients with bilateral carotid artery occlusive diseases improves cerebral hemodynamics not only on the side of CAS but also on the other side. Split-dose iodine-123I-IMP SPECT is useful for evaluating the hemodynamic status in bilateral carotid artery occlusive diseases.