Knowledge of the bleeding risk and the long-term outcome of conservatively treated patients with cavernous malformations (CM) is poor. In this work, we studied the occurrence of CM-associated hemorrhage over a 10-year period and investigated risk factors for bleeding. Our institutional database was screened for patients with cerebral (CCM) or intramedullary spinal cord (ISCM) CM admitted between 2003 and 2021. Patients who underwent surgery and patients without completed follow-up were excluded. Analyses were performed to identify risk factors and to determine the cumulative risk for hemorrhage. A total of 91 CM patients were included. Adjusted multivariate logistic regression analysis identified bleeding at diagnosis (p = 0.039) and CM localization to the spine (p = 0.010) as predictors for (re)hemorrhage. Both risk factors remained independent predictors through Cox regression analysis (p = 0.049; p = 0.016). The cumulative 10-year risk of bleeding was 30% for the whole cohort, 39% for patients with bleeding at diagnosis and 67% for ISCM. During an untreated 10-year follow-up, the probability of hemorrhage increased over time, especially in cases with bleeding at presentation and spinal cord localization. The intensity of such increase may decline throughout time but remains considerably high. These findings may indicate a rather aggressive course in patients with ISCM and may endorse early surgical treatment.