Stroke is an important complication following allogeneic hematopoietic stem cell transplantation (allo-HSCT). Nevertheless, few studies have been published to analyzed the occurrence and prognosis of stroke after allo-HSCT. From January 2007 to December 2018 in Peking University People's Hospital, 6449 patients received HSCT and there were 2.3% of patients diagnosed with stroke after allo-HSCT (hemorrhagic: 1.0%, ischemic: 1.3%). The median time to hemorrhagic and ischemic stroke after HSCT was 161 days and 137 days, respectively. In total, 8.4% of patients experienced neurological sequelae. The outcome was much worse in patients with stroke than in control subjects. The comparison of prognosis showed no statistical differences between patients with hemorrhagic stroke and those with ischemic stroke. Significant risk factors for hemorrhagic stroke were pretransplant central nervous system leukemia (CNSL), and delayed platelet engraftment. Risk factors associated with the occurrence of ischemic stroke included high-risk disease, prior venous thromboembolism (VTE), grade III-IV acute graft-versus-host disease (aGVHD), and thrombotic microangiopathy (TMA). Haplo-identical transplantation was not a risk factor for stroke and had no impact on the prognosis compared with HLA-matched HSCT. Altogether, these results show that stroke is a severe complication after allo-HSCT. The prognosis of posttransplant stroke did not differ between hemorrhagic and ischemic stroke.