Background: Primary brain tumors are relatively rare malignancy, with high-grade gliomas (glioblastoma multiforme and anaplastic gliomas) are the most common types . We aimed to evaluate the prognostic value of Prognostic Nutritional Index (PNI), which is calculated by lymphocyte count and albumin, in recurrent high-grade glioma patients treated with systemic treatment.Methods: Data of 92 patients with recurrent high-grade glioma who received systemic treatment and followed in our clinic between 2012-2018 was retrospectively collected and analyzed. PNI was calculated as: [(10 × serum albumin (g/dL)) + (0.005 × total lymphocyte count)]. Patients were categorized according to the median PNI value. We investigated the prognostic role of PNI groups, and survival outcomes.Results: Median value of PNI was 46.02, and median follow-up duration was 9 months (1-68 months). Median overall survival (OS) was 8.1 months (95%CI: 6.04-10.3). Median OS was significantly longer in patients with PNI> 46.02 compared to patients with PNI ≤ 46.02 (13.9 months (95%CI: 9.8-18.1), and 6.07 months (95%CI: 4.3-7.7), p=0.01, respectively). In multivariate analysis, PNI was found to be an independent prognostic factor for OS [HR:0.54(95%CI:0.3-0.97), p=0.03)].Conclusion: In our study, the PNI was found to be an independent prognostic biomarker in patients with recurrent high-grade gliomas, but further prospective trials are necessary to validate its prognostic role.