Background and Purpose-Evidence on the natural history of hemorrhagic moyamoya disease is still insufficient. We investigated the incidence of recurrent intracranial bleeding, mortality, and risk factors for rebleeding in patients with moyamoya disease. Methods-A total of 128 conservatively managed patients with hemorrhagic presentation and complete follow-up data were included. Recurrent hemorrhages during long-term follow-up were documented. Annual and cumulative incidence rate of bleeding was generated via Kaplan-Meier survival analysis, and risk factors were analyzed using logistic regression analysis. Results-The median follow-up time was 10.1 (1-27) years. During a total of 1300.7 patient-years, 47 (36.7%) patients experienced 59 occurrences of recurrent hemorrhages, rendering an average annual incidence of 4.5%. Among them, 9 patients (19.1%) died from rebleeding and 12 patients sustained severe disability (modified Rankin Scale score of >= 3). The cumulative risk of rebleeding was 7.8% at 5 years, 22.6% at 10 years, and 35.9% at 15 years. Only 4 (3.1%) patients experienced ischemic stroke, yielding an average annual incidence of 0.3%. Multivariate analysis showed that smoking (odds ratio, 4.85; P=0.04) was an independent risk factor of rebleeding. Rebleeding (hazard ratio, 11.04; P=0.02) and hypertension (hazard ratio, 4.16; P=0.04) were associated with increased mortality. Age, type of initial bleeding, digital subtraction angiography staging, family history, and coexisting cerebral aneurysms were not associated with increased risk of rebleeding. Conclusions-Rebleeding events were common and the main cause of death in patients with hemorrhagic moyamoya disease. The risk of rebleeding steadily increased during long-term follow-up. Smoking was a risk factor for rebleeding, and hypertension was associated with increased mortality.