Purpose : To evaluate the efficacy and limitation of intra-arterial urokinase (IAUK) infusion for treatment of acute cerebral stroke. Materials and Methods : Twenty-seven acute cerebral stroke patients treated with IAUK infusion within six hours of stroke onset were reviewed. All patients showed normal initial brain findings on CT. In 21 patients, urokinase(5-15 $ imes$ $10^5$IU) was administered through a microcatheter placed into or proximal to occluded segment. Mechanical disruption of thrombus by guidewire was performed in 17 patients. Angiographic and clinical responses and complications after IAUK infusion, were evaluated and the results were compared with those of intravenous heparin(N=19) and urokinase infusion(n=19). Results : Complete or partial angiographic recanalization of occluded segment was found in 18 patients(67%), and neurologic improvement was followed in 14patients(52%). The degree of improvement on the stroke scale score after IAUK infusion was statistically more significant(p<0.05) than that shown after intravenous heparin and urokinase infusion. Complications after IAUK infusion were large(15%) and small amount intracerebral hemorrhage(15%), contrast leakage into brain parenchyma(11%), and gastrointestinal bleeding(4%). Between the IAVK and the intravenous urokinase infusion group, differences in extent and types of complications were statistically insignificant, but were significantly higher in those two groups than in the intravenous heparin infusion group. Conclusion : IAUK infusion may be effective for the treatment of acute cerebral stroke.