PURPOSE: To describe a case of normal-tension glaucoma with bilateral complete occlusion of the internal carotid artery. METHODS: A 58-year-old man who had a 2-year history of normal-tension glaucoma in the left eye presented with ocular ischemic syndrome. To evaluate the orbital circulation, cerebral angiography and color Doppler imaging were performed. RESULTS: Cerebral angiography showed bilateral complete occlusion of the internal carotid artery and collateral blood supply through the right and left ophthalmic arteries, in which the flow was reversed. Moreover, color Doppler imaging revealed lower blood flow velocities in the left central retinal and short posterior ciliary arteries, suggesting a steal phenomenon. CONCLUSION: Normal-tension glaucoma in the present case may be caused by chronic reduction of retrobulbar blood flow resulting from a steal phenomenon.