This chapter presents a brief description of some uncommon vascular disorders that can characteristically cause epilepsy and/or seizures. The epilepsy is usually not the main clinical problem. In cases with moyamoya syndrome, the prognosis depends upon identification and treatment of the underlying cause of the condition. A seizure, which results in recategorization as eclampsia, may occur before, during, and after delivery. The cerebral vascular changes most commonly occur in the posterior circulation and have features such as hypertensive encephalopathy, including cerebral edema. Thrombosis of the cerebral venous system is less common than in the arterial system. The autoimmune state, characterized by the presence of antiphospholipid antibodies, may cause thrombosis both in arteries and in veins. The isolated angiitis is probably an inflammatory reaction caused by a variety of disorders, such as infections, but also cerebral amyloid angiopathy. Treatment of the arteritis includes corticosteroids, often in combination with other immunosupressive drugs.