We conducted a pilot study to evaluate the possibility that the intraarterial thrombolytic therapy might leadto recanalization of the acutely occluded cerebal arteries and subsequent clinical improvement in patients withacute cerebral infarction. Mean time from the onset of symptoms to the start of treatment and mean dosage ofthrombolytic agent, Urokinase, were 6.4 hours and 1,260,000 units, respectively. Seven of 12 cases(58%) with acutecerebral infarction demonstrated successful recanalization. Neurological evaluation at one week and three monthsafter the onset of symptoms suggested better outcome in the cases with recanalization. Repeat CT scan at 24 hoursand one week after the procedure demonstreated the evidence of hemorrhagic infaction in the infarcted territoriesin five cases (41%), but clinical deteriorations were observed in only 2 cases. Though statistical analysis couldnot be done because the limited number of cases, these results suggest that the intra-arterial thrombolytictherapy had a role in the management of acute cerebral infarction.