OBJECTIVE: To elucidate the clinical features of patients with hemorrhagic moyamoya disease (MMD) in China. METHODS: We retrospectively reviewed 471 patients with hemorrhagic MMD at Beijing Tiantan Hospital. Clinical features and radiologic findings were analyzed. RESULTS: The mean age at diagnosis was 35.3 +/- 11.5 years, with 1 peak distribution in patients from 35 to 39 years of age. The ratio of women to men was 1.2:1. Familial occurrence was 3.8%. The primary symptoms at initial presentation were intraventricular hemorrhage (42.0%), intracerebral hemorrhage (23.6%), intracerebral hemorrhage with intraventricular hemorrhage (18.3%), and subarachnoid hemorrhage (16.1%). Before the diagnosis, 68 patients experienced a second episode of bleeding. Rebleeding tends to be common within 6 years after the first bleeding (83.8%). The second bleeding episode was characterized by a change in which hemisphere bleeding occurred in 7 patients (10.3%) and by the type of bleeding in 23 patients (33.8%). Most patients presented with Suzuki stage 3 or 4 MMD (61.7%). Posterior cerebral artery involvement was observed in 28 (18.4%) patients. Forty-three intracranial aneurysms were identified in 39 patients (8.3%). CONCLUSIONS: A 1-peak pattern in age distribution and mild female dominance in sex distribution were observed in patients with hemorrhagic MMD. Rebleeding tends to be common within 6 years after the first bleeding; however, some cases of rebleeding occur after a long period. Furthermore, the second bleeding episode was characterized frequently by a change in hemisphere and the type of bleeding. Early surgical treatment in both hemispheres is recommended.