We report on the results of intra-arterial thrombolysis in 11 patients with vertebrobasilar artery occlusion treated within 6 hours after onset of symptoms. Urokinase (5 patients) or recombinant tissue plasminogen activator (t-PA) (6 patients) was injected through a microcatheter conducted to the thrombus. Eight patients showed recanalization of the thrombus. The outcome was excellent in 5 patients, good in 2 patients, and poor in one patient. Recanalization could not be achieved in 3 of the 11 procedures; all patients in whom recanalization failed died. There were no hemorrhagic complications after thrombolysis. Two patients with residual stenosis after thrombolysis underwent successful percutaneous transluminal angioplasty (PTA) to prevent re-occlusion. Intra-arterial thrombolysis for vertebrobasilar artery occlusion is a safe and effective treatment if it is performed within 6 hours.