Copyright © 2019 the Author(s). Published by Wolters Kluwer Health, Inc.This retrospective analysis of patients aims to show the blood levels of preoperative inflammatory markers in patients with glioblastoma and brain metastasis and to provide the diagnostic accuracy of the neutrophil-lymphocyte (NLR), lymphocyte-monocyte (LMR), and platelet-lymphocyte (PLR) ratios between the 2 groups of patients.The retrospective reviews of the neutrophil, lymphocyte, monocyte, and platelet counts were analyzed in 80 patients with newly diagnosed glioblastoma and 70 patients with brain metastasis. The NLR, LMR, and PLR were calculated in each group. The differences in all the parameters were compared between the 2 groups.Although the neutrophil, monocyte, and platelet counts were higher and the lymphocyte count was lower in patients with metastasis, the difference was not significant. A significantly higher PLR (P=.004) and a lower LMR (P=.01) were found in patients with brain metastasis. Although both PLR and LMR had diagnostic accuracy in differentiating glioblastoma from brain metastasis, LMR showed the highest diagnostic accuracy. NLR showed no diagnostic accuracy.Systemic inflammation is more severe in glioblastoma than in brain metastasis, and LMR is more sensitive and/or specific than PLR in differentiating glioblastoma from brain metastasis. Therefore, LMR (less likely PLR) can be used as an index for differentiating between glioblastoma and brain metastasis before surgery.