To assess the efficacy of percutaneous transluminal angioplasty. A retrospective case study covering the period January 1990 to December 1992. A tertiary-care referral centre. Thirteen patients, ranging in age from 23 to 57 years, who had suffered an aneurysmal subarachnoid hemorrhage and subsequent symptomatic vasospasm that had not responded to aggressive medical therapy. Percutaneous transluminal angioplasty of spastic cerebral arteries Neurologic improvement (improved level of consciousness or resolution of focal deficit) immediately after angioplasty and functional status at 6 months after angioplasty. Four (31%) patients showed neurologic improvement immediately after angioplasty. At 6 months, 5 (38%) of the 13 were independent, 2 (15%) were dependent (severely disabled), and 6 (46%) had died. Poor clinical grade at the time of angioplasty was associated with a poor outcome. Percutaneous transluminal angioplasty appears to be a safe procedure that is beneficial in some patients with symptomatic vasospasm refractory to aggressive hypervolemic, hypertensive therapy. The best results likely are obtained in patients of good clinical grade in whom new neurologic deficits have not become established, and angioplasty should not be delayed if medical therapy does not rapidly reverse the symptoms of vasospasm.