This study was undertaken to evaluate indication and efficacy of intra-arterial thrombolysis for 20 consecutive patients with vertebrobasilar artery occlusion by stroke MRI findings, including diffusion weighted imaging (DWI) and MR angiography in the acute stage. The age ranged from 41 to 87 years old (a mean of 69.0). National Institutes of Health Stroke Scale (NIHSS) distributed between 1 and 28 (a mean of 11.4). All patient underwent stroke MRI examination before the treatment. We established new DWI scoring, depending on the infarction size and location, from one to five points. One point was given for brain stem infarction less than 0.5cm, two points between 0.5cm and 1cm, and three points for more than 1cm in greatest diameter of brain stem blight signal. If the infarcts were located cerebellum, thalamus or occipital lobe, one point was given for single ischemic lesion and two points for two or more lesions. Revascularization was obtained in 12 of 14 patients by intra-arterial thrombolysis, urokinase administration with or without balloon angioplasty in the acute stage. One patient who failed to have recanalization deceased. Average DWI score before treatment was 2.4 in 12 patients with recanalization group, 2.0 in 2 patients with non-recanalization group, and 1.7 in 5 patients with conservative treatment group. In 14 patients with endvascular treatment group, average DWI score in patients with modified Rankin Scale (mRS) 0-2 at 90 days was 1.17±1.07, whereas the score in patients with mRS3-6 was 3.25±1.09 (p=0.006). Our results suggest that the new DWI score could be the good predictor to evaluate the indication and efficacy of intra-arterial thrombolysis for occlusion of vertebrobasilar artery in the acute stage.