Two cases of isolated dissection of the basilar artery responsible for ischemic stroke are reported. This rare condition is still associated with a poor outcome. Most patients were male and the clinical presentation consisted of ischemic symptoms or subarachnoid hemorrhage in posterior circulation. Angiography and Magnetic Resonance Imaging are usefull for the diagnostic, showing parietal hematoma, or as for our first case, double lumens. Optimal therapeutic is unknown.