Migraine, a common disorder of uncertain pathogenesis, is linked to ischemia in a variety of ways. In some cases the relationship is coincidental. In others, migraine may be causally related to stroke, although the mechanism of migrainous stroke, if not due to arterial dissection, is unclear. In young women, additional risk factors for stroke such as cigarette smoking, use of combined oral contraceptives and anticardiolipin antibody immunoreactivity may potentiate migraine, especially migraine with aura, as a stroke risk factor. The complexity of the relationship is highlighted in certain genetic conditions such as cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy and mitochondrial encephalopathy with lactic acidosis and stroke in which migraine and stroke are both prominent clinical features.