We aimed to evaluate survival and prognostic factors in our cases diagnosed with Glioblastoma Multiforme (GBM). 69 cases treated with a median of 5980 cGy (3400-6090) radiotherapy (RT) between 2015 and 2020 were evaluated on August, 2021. The median follow-up was 12 months (2-68), and median age was 60 (39-77). Total excision, subtotal excision and biopsy were performed in 81%, 15% and 4% of patients, respectively. Concomitant or concomitant and adjuvant or adjuvant temozolomide (TMZ) was administered to 10% and 72% and 9% of cases, respectively. In the first evaluation after RT, there was 89% (56/63) local control and 11% progression (7/63). Neurological improvement was observed in 26% (10/38) of cases. Relapse was observed in a median of 7 months (3 -46) in 80% of cases (50/62) and 85% of cases (55/66) were progressed at the last control. The median and 2 -year overall survival (OS) was 12 months (3-69), and 17%, while for disease-free survival (DFS) was 7 months (3-55), and 9%, respectively, for all cases. The median OS (18 vs 5 months, p < 0.005) and DFS (13 vs 5 months, p= 0.022) were found better in those who received conventional RT and concomitant TMZ than those who received RT alone in univariate analysis. In the multivariate analysis, Karnofsky performance score ≥ 80 after RT, ≥ 5 courses of adjuvant TMZ, and RT dose ≥ 40 Gy were found significant for OS (p < 0.05). In a randomized study, 2-year OS was reported as 27% (vs 11%) in those who received conventional 60 Gy RT and concomitant TMZ compared RT alone. Conventional 60 Gy RT with concurrent and adjuvant TMZ is the standard treatment approach in patients with GBM who have good prognostic factors, and in our study, 2-year OS was obtained in 25% of these cases.