Aim:This study aimed to retrospectively evaluate the overall survival (OS) of patients with brain metastases (BMs) who had been treated with whole brain radiotherapy (WBRT) and Gamma Knife (GK) according to prognostic factors and prognostic index scores.Material and Methods:The study included 91 patients with BMs who had been treated with WBRT and/or GK between 2014 and 2017. The patients with BMs were retrospectively evaluated regarding age, sex, Karnofsky Performance Status (KPS), recursive partitioning analysis (RPA) class, basic score for BM (BS-BM), Graded Prognostic Assessment (DS-GPA) index, primary tumour type, extracranial metastases, primary tumour control, number of BMs, and brain metastasectomy. A univariate analysis of the OS was performed using the Kaplan-Meier method, supplemented by the log-rank test. We also applied a multivariate survival analysis using the Cox regression model.Results:The median OS for all patients with BMs was 6 months. Meanwhile, the median OSs for those with WBRT, GK, and WBRT-GK treatment were 6, 4, and 15 months, respectively (p = 0.00). In the multivariate analysis, the female sex (p = 0.030), brain metastasectomy (p = 0.047), treatment with WBRT-GK (p = 0.001), and the controlled primary tumour (p = 0.007) significantly correlated with the OS. Furthermore, the BS-BM (p = 0.022) was closely related with the OS compared to the RPA and DS-GPA in the multivariate analysis.Conclusion:The BS-BM was found to better predict the survival of patients with BMs according to the prognostic index scores in the multivariate analysis. Thus, our data suggest that the BS-BM is the most appropriate prognostic index.