OBJECTIVE Symptomatic cerebral vasospasm is a major cause of disability and death in patients with aneurysmal subarachnoid hemorrhage. The purpose of this study was to determine the efficacy of intra-arterial infusion (IAF) of fasudil hydrochloride for symptomatic vasospasm in terms of neurological improvement and the angiographic features of cerebral vessels. METHODS A consecutive series of 23 patients underwent IAF therapy for the treatment of symptomatic vasospasm after subarachnoid hemorrhage. Angiographic vasospasm was assessed before and after the IAF treatment. Immediate clinical effect was assessed within 24 hours after the IAF treatment, and the Glasgow Outcome Scale was used to evaluate late clinical outcome at 3 months after the onset. RESULTS IAF treatment was performed on 34 occasions for 23 patients (16 women, 7 men). Angiographic improvement was observed on all occasions (100%), and immediate clinical improvement was observed on 15 occasions (44.1%). At 3-month follow-up, 15 patients (65.2%) showed good recovery or moderate disability on the Glasgow Outcome Scale. CONCLUSIONS IAF therapy was effective in dilating spastic arteries, and clinical improvement was observed in approximately half of the fasudil hydrochloride infusions. Our findings suggested that the IAF therapy was safe and effective for patients with symptomatic vasospasm after subarachnoid hemorrhage.