Background: Intravenous thrombolysis (IVT) therapy with recombinant tissue plasminogen activator (rtPA) in acute ischemic stroke (AIS) has a known risk of intracerebral hemorrhage (ICH). We aimed to identify the predictive value of coagulation factor XIII (FXIII) on post-thrombolytic ICH risk in AIS patients. Methods: The study cohort included 69 diagnosed AIS patients undergoing IVT treatment within 24 hours of symptom onset. Blood samples taken on admission were analyzed for FXIII antigen levels with an automated latex enhanced immunoassay. Conventional coagulation parameters including prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen (FIB), and D-dimer (DD) were also tested. Results: Of the 69 AIS patients, 23 (33.3%) developed post-thrombolytic ICH. Plasma FXIII levels showed a significant decrease, accompanied with elevated FIB and DD levels in AIS patients with post-thrombolytic ICH. Multivariable logistic regression (LR) revealed that FXIII and FIB were independently associated with post-thrombolytic ICH progression. Area under receiver operating characteristic curve of FXIII selected by the further forward logistic regression was 0.823 [95% confidence interval (CI): 0.712-0.904], and the cutoff value of 76.6% yielded good sensitivity at 91.3% and good negative predictive value (NPV) at 93.9%. Conclusions: Our findings indicated that plasma FXIII level may be an independent determinant for predicting post-thrombolytic bleeding risk in AIS patients.