Objective To identify predictors of antithrombotic treatment in neonates with cerebral sinovenous thrombosis (CSVT) in a large multinational study. Study design Neonates with CSVT from 10 countries were enrolled in the International Pediatric Stroke Study from 2003 through 2007. Term neonates with CSVT who presented with neurologic symptoms or signs of systemic illness and neuroimaging evidence of thrombus or flow interruption within cerebral venous system were included. Results Of 341 neonates enrolled, 84 had isolated CSVT. Neuroimaging findings, available in 67/84 neonates, included venous ischemic infarction in 5, hemorrhagic infarction or other intracranial hemorrhage in 13, both infarction and hemorrhage in 26, and no parenchymal lesions in 23. Treatment data, available in 81/84 neonates, included antithrombotic medications in 52% (n = 43), comprising heparin (n = 14), low molecular weight heparin (n = 34), warfarin (n = 1), and aspirin (n = 2). By univariate logistic regression analysis, deep venous system thrombosis ( P = .05) and location in the United States ( P = .001) predicted nontreatment. Presence of infarction, hemorrhage, dehydration, systemic illness, and age did not predict treatment or nontreatment. In multivariate analysis only geographic location remained significant. Conclusions In neonatal CSVT, regional antithrombotic treatment practices demonstrate considerable variability and uncertainty about indications for antithrombotic therapy. Additional studies are warranted.