OBJECTIVE The use of anticoagulation to prevent venous thromboembolism (VTE) is controversial in the setting of neurosurgical decompression for traumatic subdural hematoma (SDH). In these patients, there is concern that antico-agulation may cause secondary hemorrhage, increasing the risk of death , other complications. Patients with a his-tory of anticoagulant use are at further risk of VTE, but the effect of VTE prophylaxis (VTEP) following neurosurgery for SDH has not been thoroughly investigated in this population. This study aims to investigate the differences in in-hospital outcomes in patients with SDH and preexisting anticoagulant use who received VTEP following neurosurgical interven-tion compared with those who did not. METHODS The National Trauma Data Bank was queried from 2017 to 2019 for all patients with preexisting anticoagu-lant use presenting with an SDH who subsequently underwent neurosurgical intervention. Patients who received VTEP were propensity score matched with patients who did not based on demographics, insurance type, injury severity , comorbidities. Paired Student t-tests, Pearson's chi-square tests, and Benjamini-Hochberg multiple comparisons correc-tion were used to compare differences in in-hospital complications, length of stay (LOS), and mortality rate between the two groups. A logistic regression model was developed to identify risk factors for in-hospital mortality. RESULTS Two thousand seven hundred ninety-four patients matching the inclusion criteria were identified, of whom 950 received VTEP. Following one-to-one matching and multiple comparisons correction, the VTEP group had a lower mortality rate (18.53% vs 34.53%, p < 0.001) but longer LOS (14.09 vs 8.57 days, p < 0.001) and higher rates of pressure ulcers (2.11% vs 0.53%, p = 0.01), unplanned intensive care unit admission (9.05% vs 3.47%, p < 0.001), and unplanned intubation (9.47% vs 6.11%, p = 0.021). The multivariable logistic regression showed that use of unfractionated heparin (UH; OR 0.36, p < 0.001) and low-molecular-weight heparin (LMWH; OR 0.3, p < 0.001) were associated with lower odds of in-hospital mortality. CONCLUSIONS In patients with traumatic SDH and a history of anticoagulant use, perioperative VTEP was associated with increased LOS but provided a mortality benefit. LMWH and UH use were the strongest predictors of survival.