Purpose: Surgical resection of glioblastoma (GB) extends survival; however, at what age does surgery no longer prolong a reasonable quality of life. We examined post-operative functional independence (FI) as a proxy for quality of life in elderly patients. Methodology: Records of patients 60 years and older who underwent surgical intervention for a GB at a single centre between August 2000 and September 2018 were retrospectively reviewed. Duration of FI post-op was determined by the first documented loss of independence with activities of daily living. Pre-op factors associated with mortality were assessed with a multivariate analysis and logistic regression model. A prognostic tool for morbidity and mortality was developed using a jackknife (hold-one-out) method for good out-of-sample performance. Results: In total, 352 patients had a mean age of 69.1±6 years and a median survival of 7.1 months post-operation. Median months of FI was 1.3, improving to 2.7 following sub- or gross-total resections, but was 0 for those who had biopsies. In patients aged 60-64.9 years undergoing surgical resection, 74.2% (49 out of 66 patients) had FI post-op, whereas only 8.3% (1 out of 12 patients) of those 75 years and older having biopsies retained FI. Advancing age (p=0.0005), declining Karnofsky Performance Status score (p=0.007), and the presence of multifocal (p=0.002) and bilateral tumours (0.001) were significantly associated with decreased survival post-op. The prognostic models for morbidity and mortality had areas under the curve of approximately 0.72. Conclusion: Performing biopsies in patients 75 years and older does not allow them to retain or regain FI and instead adds to their physical burden for their remaining days.