OBJECTIVE: To elucidate the clinical features, surgical treatment, and long-term outcome in elderly patients with moyamoya disease (MMD). METHODS: We retrospectively reviewed 87 elderly patients with MMD at Beijing Tiantan Hospital. Clinical features, radiologic findings, and outcomes were analyzed. RESULTS: The mean age at diagnosis was 54.0 +/- 3.7 years. Familial occurrence was 2.3%. Underlying vascular risk factors was 74.7%. Infarction was the most common symptom in elderly MMD (40.2%). Most patients presented with Suzuki stage 4 or 5 MMD (51.2%). Posterior cerebral artery involvement was observed in 22 (25.3%) patients. The incidence of postoperative infarction or hemorrhages was 6.9%. Diabetes was identified as a predictor of adverse postoperative events. During the average follow-up of 35.5 +/- 22.2 months, rebleeding in patients with hemorrhagic MMD was higher than in those with ischemic MMD (P < 0.05). What's more, the rate of perfusion improvement in surgically treated patients was higher than in conservatively treated patients 3 months after discharge (P < 0.05). CONCLUSIONS: Infarction was the most common symptom in elderly MMD. More vascular risk factors, a higher grade of Suzuki stage, fewer familial cases, and posterior cerebral artery involvement were observed in elderly patients with MMD. Diabetes was a risk factor of postoperative events for elderly patients. Hemorrhagic MMD had a higher rate of rebleeding than the ischemic type. Although surgical revascularization procedures can improve cerebral perfusion, further study is needed to determine whether surgical revascularization is effective in elderly patients or with certain techniques.