Background: Elderly GB patients have a dismal prognosis. The optimal treatment in this population remains to be established. Methods: We performed a multicenter retrospective and prospective study of newly diagnosed GB patients (pts) treated with standard Ch-RT (Stupp regimen). In the present substudy we analyzed clinical outcome and prognostic factors in elderly ( > 65 y) pts and compare these to younger pts from the global cohort. Results: Between 2005 to 2014, 432 pts were enrolled. There were 148 > 65y; 117 (79%) 65-75y and 31 (21%) > 75y with a mean age of 72y, mean KPS 80%, and 58.8% were males. In pts > 65y, gross total resection (GTR) was performed in 34 (24.5%), and biopsy in 29 (20.9%) with postoperative complications in 17 (11.5%). The time to initiate Ch-RT was 4.93 weeks (w); 127 (85.8%) finished Ch-RT and 109 (73.6%) completed adjuvant temozolomide (TMZ). Only 16 (10.8%) could discontinue steroids during the concomitant therapy. There were 28 (18.9%) patients with pseudoprogression. MGMT methylation status was studied in 103 pts of which 57 (55.3%) were methylated. The only statistical differences between > 65 and younger pts were: lower KPS (p = 0.01) and fewer pts initiating adjuvant TMZ (p = 0.015). Median follow-up is 16.76 months. In the global population progression-free survival (PFS) and overall survival (OS) were 8 months (95% CI, 7.49-8.5) and 15 months (95% CI, 7.49-8.5), respectively, compared to 7 (95% CI, 6.1-7.8), and 11 months (95% CI, 8.7-13.2) in > 65y (p < 0.001 and p = 0.033). For elderly pts, on multivariate analysis, GTR and methylated MGMTbut not KPS were independent predictors of OS and PFS, respectively. Conclusions: Standard Ch-RT is feasible in elderly pts even though this population had poor KPS and fewer pts that could start adjuvant TMZ. As expected, PFS and OS were poorer in > 65y. For elderly patients, type of resection and MGMT methylation remain the more relevant prognostic factors in newly diagnosed GB treated with Ch-RT and adjuvant TMZ. Randomized prospective trials are warranted.