Patients presenting with symptomatic intracranial arterial vasospasm are now being treated by interventional neurovascular techniques in selected cases. From a percutaneous transfemoral approach, a custom-designed silicone microballoon can be guided through the intracranial vessels, and inflated to dilate the spastic vessel(s). This technique has been useful for both focal and diffuse areas of spasm. In clinical trials, 28 patients, ranging in age from 15-73 years have been treated. A total of 99 vascular territories have been successfully dilated in both the anterior and posterior circulations. Clinical improvement following treatment was observed in 17 cases (60.7%). Technical complications directly related to therapy included 2 cases (7.1%) of vessel rupture. In long term clinical follow-up 17 patients (60.7%) had good to excellent outcome, 2 patients (7.1%) remained in poor condition, and 9 patients (32.1%) died despite therapy. In patients presenting with symptomatic intracranial arterial vasospasm who are unresponsive to medical therapy, treatment by balloon angioplasty techniques may help to improve cerebral perfusion and clinical outcome of the patient.