The spleen is a crucial organ in humans. Little is known about the association between stroke and splenic injury or splenectomy. The aim of this study was to determine the risk of stroke in patients with splenic injury and splenectomy.A nationwide cohort study was conducted by analyzing the National Health Insurance Research Database in Taiwan. For comparison, control patients were selected and matched with splenic injury patients in a ratio of 4:1 according to age, sex, and the year of hospitalization. We analyzed the risks of stroke using a Cox proportional-hazards regression analysis.A total of 11,273 splenic injury patients, including 5294 splenectomized and 5979 nonsplenectomized patients, and 45,092 control patients were included in this study. The incidence rates of stroke were 8.05, 6.53, and 4.25 per 1000 person-years in splenic injury patients with splenectomy, those without splenectomy, and the control cohort, respectively. Compared with the control cohort, splenic injury patients with splenectomy exhibited a 2.05-fold increased risk of stroke (95% confidence interval [CI] 1.8-2.34), whereas those without splenectomy exhibited a 1.74-fold increased risk (95% CI 1.51-2). Splenectomy entailed an additional 1.21-fold increased risk of stroke compared with nonsplenectomy in patients with splenic injury.This study revealed that splenic injury and splenectomy were significantly associated with an increased risk of hemorrhagic and ischemic strokes. The results of this study may alert physicians and patients to the complications of splenic injury and splenectomy.