Background: Hemorrhagic Moyamoya disease (MMD) is a common subtype of MMD in adult patients, especially in East Asian countries. To our knowledge, current studies regarding factors affecting the prognosis in patients with hemorrhagic MMD is lacking. This study aimed to determine the potential prognostic factors for hemorrhagic MMD.Methods: This retrospective study reviewed patients with hemorrhagic MMD diagnosed at our hospital between June 2011 and June 2021. Patient outcome was measured at discharge using the extended Glasgow outcome scale (GOSE). Prognostic factors were assessed by multivariate logistic regression analysis.Results: Patients discharged with worst outcomes (GOSE 1 and 2) had significantly lower initial Glasgow coma scale (GCS) scores (5.9 ± 3.1 vs. 10.3 ± 3.7; P = 0.002) and were associated with more severe intraventricular hemorrhage (IVH) (P = 0.007), and IVH-related hydrocephalus requiring extraventricular drain (EVD) insertion was more common (n = 12 vs. n = 7; P = 0.001). The multivariate analysis showed that IVH-related hydrocephalus requiring EVD placement (OR 8.256, 95% CI 0.996–68.450; P = 0.016) and low initial GCS scores (OR 0.644; 95% CI 0.465–0.892; P = 0.008) were independent risk factors for unfavorable outcomes (GOSE 1–4) in patients with hemorrhagic MMD.Conclusion: This study analyzed several potential prognostic factors for patients with hemorrhagic MMD. Low initial GCS scores and IVH-related hydrocephalus requiring EVD insertion were related to unfavorable outcomes.