Survival of elderly patients with glioblastoma (GBM) is poor, but improves with tumor resection and radiotherapy (RT). Concurrent temozolomide (TMZ) chemotherapy during RT improves the survival of younger patients with GBM, but the benefit in elderly patients is unclear. Medical records of patients ≥65 years old with primary GBM, histologically confirmed at Memorial Sloan-Kettering Cancer Center and treated with RT, were reviewed. Survival was associated with patient (age, performance status), tumor (single or multiple), and treatment (extent of surgery, RT field, technique, fractionation and use of concurrent TMZ) characteristics in a multivariable Cox regression model. Grade ≥3 hematologic toxicity rates were compared to reported rates in younger patients. Median age of the 291 patients studied was 71 years. Longer survival was associated with younger age, tumor resection, and concomitant TMZ and RT (p < 0.01). Concurrent TMZ and RT improved median survival of patients with favorable prognostic factors from 12 to 21 months and from 10 to 13 months in patients 65-70 and ≥71 years old, respectively. Concomitant TMZ and RT increased the 2 year OS rate from 14 to 41 % and from 5 to 24 % in patients 65-70 and ≥71 years old, respectively. Grade 3-4 thrombocytopenia was significantly more frequent in the present cohort. Survival of elderly patients with GBM may be prolonged with the use of concomitant TMZ during RT. An ongoing randomized study will determine the benefit of this approach in a prospective fashion.