Background: Hemorrhagic stroke in young patients with sickle cell anemia remains poorly characterized. Methods: The Post-STOP (Stroke Prevention Trial in Sickle Cell Anemia) retrospective study collected follow-up data on STOP and STOP II clinical trial cohorts. From January 2012 to May 2014, a team of analysts abstracted data from medical records of prior participants (all with sickle cell anemia). Two vascular neurologists reviewed data to confirm hemorrhagic strokes defined as spontaneous intracerebral, subarachnoid, or intraventricular hemorrhage. Incidence rates were calculated using survival analysis techniques Results: Follow-up data were collected from 2850 of 3835 STOP or STOP II participants. Patients (51% male) were a median of 19.1 (interquartile range, 16.6-22.6) years old at the time of last known status. The overall hemorrhagic stroke incidence rate was 63 per 100 000 person-years (95% CI, 45-87). Stratified by age, the incidence rate per 100 000 person-years was 50 (95% CI, 34-75) for children and 134 (95% CI, 74-243) for adults >18 years. Vascular abnormalities (moyamoya arteriopathy, aneurysm or cavernous malformation) were identified in 18 of 35 patients with hemorrhagic stroke. Conclusions: The incidence rate of hemorrhagic stroke in patients with sickle cell anemia increases with age. Structural vascular abnormalities such as moyamoya arteriopathy and aneurysms are common etiologies for hemorrhage and screening may be warranted.