We conducted a pilot study to evaluate the possibility that the intraarterial thrombolytic therapy might lead to recanalization of the acutely occluded cerebral arteries and subsequent clinical improvement in patients with acute cerebral infarction. mean time from the onset of symptoms to the start of treatment and mean dosage of thrombolytic agent, Urokinase, were 6.4 hours and 1,260,000 units, respectively. Seven of 12 cases(58%) with acute cerebral infarction demonstrated successful recanalization. neurological evaluation at one week and three months after the onset of symptoms suggested better outcome in the cases with recanalization. Repeat CT scan at 24 hours and one week after the procedure demonstreated the evidence of hemorrhagic infaction in the infarcted territories in five cases(41%), but clinical deterorations were observed in only 2 cases. Though statistical analysis could not be done because the limited number of cases, there results suggest that the intra- arte ial thrombolytic therapy had a role in the management of acute cerebral infarction.