OBJECT The aim of this study was to describe the baseline clinical features and long-term outcomes of patients with moyamoya disease (MMD) based on a 25-year period at a single center in China. METHODS Data obtained in 528 consecutive patients with MMD treated at the authors' hospital from 1984 to 2010 were reviewed retrospectively. Events of transient ischemic attack, new infarction, and hemorrhage were included. The Kaplan-Meier risk of stroke was calculated. RESULTS The mean (+/- SD) patient age was 26 +/- 13 years (range 2-67 years), and the female/male ratio was 0.9:1. There were 332 cases of ischemia and 196 hemorrhages. Adults had a higher rate of bleeding than children (50.7% vs 14.0%, respectively; p < 0.001). One hundred twenty-two patients were treated conservatively, and 406 patients underwent revascularization procedures. Of 528 patients, 331 (62.7%) had at least 1 year of follow-up (median 39.5 months) and data from these patients were analyzed. Rebleeding and mortality rates in patients with hemorrhagic MMD (n = 104) were higher than in those with ischemic MMD (n = 227) (26.9% vs 2.2% [p < 0.001] and 4.8% vs 0.4% [p < 0.05], respectively). Twenty-five of 60 (41.7%) conservatively treated patients and 8 of 271 (2.9%) surgically treated patients experienced rebleeding events, a difference that was significant in the Kaplan-Meier curve of rebleeding (p < 0.01).,An improvement in perfusion was found in 164 of 224 (73.2%) surgically treated patients 1 month after discharge. However, there was no significant difference in the rate of ischemic events in the surgical and conservative groups (18.8% and 28.3%, respectively; p = 0.09). Among the 104 hemorrhagic cases, rebleeding attacks were observed in 25 patients in the nonsurgical group (n = 60) and 3 patients in the surgical group (n = 44) (41.7% and 6.8%, respectively; OR 9.7 [95% CI 2.7-35.0]; p < 0.01). CONCLUSIONS There was no difference in the sex distribution of Chinese patients with MMD. Patients with hemorrhagic MMD had a much higher rate of rebleeding and poorer prognosis than those with the ischemic type. Surgical revascularization procedures can improve cerebral perfusion and have a positive impact in preventing rebleeding in patients with hemorrhagic MMD.