Background: Tractography has become a standard tool for planning neurosurgical operations and has been proven to be useful for risk stratification. In various conditions, tractography-derived white matter integrity has been shown to be associated with neurological outcome. Postoperative performance has been shown to be a prognostic marker in glioma. We aimed to assess the relation of preoperative corticospinal tract (CST) integrity with postoperative neurological deterioration in patients with malignant glioma. Methods: We retrospectively analyzed a cohort of 24 right-handed patients (41.7% female) for perioperative neurological performance score (NPS) and applied our anatomical tractography workflow to extract the median fractional anisotropy (FA) of the CST in preoperative magnetic resonance imaging (MRI). Results: Median FA of the CST ipsilateral to the tumor correlated significantly with preoperative NPS (p = 0.025). After rank order correlation and multivariate linear regression, we found that the preoperative median FA of the right CST correlates with preoperative NPS, independently from epidemiological data (p = 0.019). In patients with lesions of the right hemisphere, median FA of the right CST was associated with a declining NPS in multivariate linear regression (p = 0.024). Receiver operating characteristic (ROC) analysis revealed an optimal FA cutoff at 0.3946 in this subgroup (area under the curve 0.83). Patients below that cutoff suffered from a decline in neurological performance significantly more often (p = 0.020). Conclusions: Assessment of preoperative white matter integrity may be a promising biomarker for risk estimation of patients undergoing craniotomy for resection of malignant glioma.