Despite modern neurosurgical technology and neuroanesthetic care, treatment of aneurysms of the distal basilar artery remains fraught with complications. Between 1982 and 1988, 126 patients with aneurysms of the distal basilar artery who had been treated by 2 surgeons were retrospectively analyzed to determine the causes of morbidity and mortality from this disease and its treatment. Ten patients (8%) died, and 14 patients (11%) suffered permanent neurological disability after treatment. The causes of failed management could be grouped into the following categories: 1) direct effects of hemorrhage; 2) errors in surgical timing; 3) conceptual errors; 4) technical errors; 5) morbidity from delayed cerebral ischemia; and 6) complications of hypertensive/hypervolemic therapy for symptomatic vasospasm; a small group of patients who died despite having received what we consider excellent management were grouped under a seventh category, "bad luck." Frequently, patients who did poorly suffered from multiple complications, each of which contributed to their overall morbidity. It is our hope that increased awareness of these potential pitfalls and the further evolution of intravascular technique in selected cases will, in time, improve the outlook for patients suffering from these dangerous lesions.