This study was designed to elucidate the clinical course of patients with vertebro-basilar arterial dissection and to show the guidelines for options of the management. Between 1992 and 2001, 23 patients were diagnosed as having vertebro-basilar arterial dissection by clinical course, magnetic resonance imaging (MRI) and angiography. The male to female ratio was 20 to 3, showing male dominance. Their clinical data were analyzed retrospectively. Fourteen cases presented with subarachnoid hemorrhage (SAH) and the other 9 with ischemic symptoms. Among those with SAH, there were 6 mortalities. The causes of mortalities were rebleeding in five cases and initial poor Hunt-Hess grade in one case. In most cases, rebleeding happened within 14 days after initial bleeding and in five patients within 4 days. Five patients were managed by surgical treatment, twelve by endovascular treatment and the other 2 by conservative management. Recently, since 1999, initially endovascular techniques had been tried to patients immediately after diagnosis and the results were good. Previous cases underwent endovascular management only when surgical treatment failed or was inappropriate. These patients showed poor prognosis. Nine cases with ischemic symptoms showed benign clinical course with no mortality and only one symptomatic recurrence following endovascular treatment. Six patients were treated by antiplatelet and/or anticoagulation therapy, two by endovascular treatment and the other one by surgery. Four of these nine patients had history of severe exercise or trauma immediately before onset of symptoms and two others had similar history several months before. In conclusion, among patients diagnosed as vertebro-basilar arterial dissection, those with SAH should be managed aggressively by either surgical or endovascular techniques because these patients showed rapid deterioration with high incidence of rebleeding and mortality. Since those with ischemic symptoms demonstrated benign clinical course, the authors recommend initial conservative management such as antiplatelet and/or anticoagulation or endovascular treatment.