To analyse the impact of age and co-morbidities on compliance and outcomes in GBM patients enrolled in three prospective phase II trials. GBM patients (≥18 years) were treated with radiotherapy (60 Gy) or enrolled in a Fractionated Stereotactic Conformal-Radiotherapy Phase II trial (69.4 Gy). Concomitant and adjuvant chemotherapy with Temozolomide (TMZ) was administered. Charlson Index Co-morbidity (CCI) was used to assess co-morbidity. Toxicity was evaluated according to RTOG score. Survival analysis was performed by the Kaplan-Maier. Influence of age and co-morbidity was evaluated using log-rank test. From 2001 to 2008, 146 patients were enrolled: 56 (38.4 %) aged over 65 and 90 under 65. CCI ≥1 was observed in 41 % of elderly and 22 % of young group. Patients' compliance was 97.9 % for radio-chemotherapy. Acute toxicity was mild with no difference between the groups. Global median progression-free survival (PFS) and overall survival (OS) were 12 and 18 months, respectively. Age, surgery and radiation dose correlated with survival (p = 0.01, p = 0.04 and p = 0.03). CCI ≤2 did not show any influence on OS. Our data show that elderly with a good performance status and few co-morbidity may be treated as younger patients; moreover, age confirms a negative impact on survival while CCI ≤2 did not correlated with OS.