A 61-year old man with a history of arterial hypertension suffered a left HZO, and was treated with acyclovir. Three weeks later he suddenly developed moderate left hemiparesis particularly of the leg, severe paresis of the right leg, aphasia and somnolence. Treated with IV acyclovir and high-dose corticosteroids deterioration of the right hemiparesis was apparent. Serological and CSF-studies showed acute varicella-zoster virus infection with intrathecal antibody synthesis (antibody specificity index 2.7). On the third day CT scan revealed infarctions in the territory of both anterior cerebral arteries, at the fifth day additionally left striatocapsular infarction. Selective carotid arteriogram showed bilateral occlusions of anterior cerebral arteries in their proximal segment. With a mean delay of seven weeks granulomatous vasculitis is a rare complication of HZO, leading commonly to ischemic infarctions in the region of the middle cerebral artery. Trigeminovascular connections are the probable pathway of virus-transmission from the trigeminal nerve to ipsilateral branches of the circle of Willis. Because of the presumed pathogenesis immediate therapy with high-dose corticosteroids and acyclovir is justified.