Sixteen patients with dissecting aneurysms or pseudoaneurysms of the vertebral artery, 12 involving the intradural vertebral artery and four occurring in the extradural segment, were treated by endovascular occlusion of the dissection site. Patients with vertebral fistulas were excluded from this study. The dissection was caused by trauma in three patients (two iatrogenic) and in the remaining 13 no obvious etiology was disclosed. Nine patients presented with subarachnoid hemorrhage (SAH), two of whom had severe cardiac disturbances secondary to the bleed. The nontraumatic dissections occurred in seven women and six men, with a mean age on discovery of 48 years. Fifteen patients were treated with endovascular occlusion of the parent artery at or just proximal to the dissection site. One patient had occlusion of a traumatic pseudoaneurysm with preservation of the parent artery. Four patients required transluminal angioplasty because of severe vasospasm produced by the presenting hemorrhage, and all benefited from this procedure with improved arterial flow documented by transcranial Doppler ultrasonography and arteriography. In 15 patients angiography disclosed complete cure of the dissection. One patient with a long dissection of extracranial origin extending intracranially had proximal occlusion of the dissection site. Follow-up angiography demonstrated healing of the vertebral artery dissection but persistent filling of the artery above the balloons, which underscores the need for embolic occlusion near the dissection site. No hemorrhages recurred. One patient had a second SAH at the time of therapy which was immediately controlled with balloons and coils. This patient and one other had minor neurological worsening resulting from the procedure (mild Wallenberg syndrome in one and minor ataxia in the second). Symptomatic vertebral artery dissections involving the intradural and extradural segments can be effectively managed by endovascular techniques. Balloon test occlusion and transluminal angioplasty can be useful adjuncts in the management of this disease.