Background: The relationship between glioblastoma extent of surgical resection (EoR) and survival is well documented.1-3 The advent of 5-aminolevulinic acid (5-ALA), a tissue selective fluorophore, has led to increased rates of gross total tumour resection.4-6 Since 5-ALA received approval for use in Canada in 2020, no Canadian centres have examined its impact on rates of complete resection (CR) for newly diagnosed high grade glioma (HGG) patients. Methods: This study evaluates the difference in EoR class7, for newly diagnosed HGG. Fifty-one consecutive patients underwent awake craniotomy with white light illumination (WLS) while 45 consecutive HGG patients were operated with fluorescence guidance (FGS). Analysis of EoR class was blinded and performed by 2 independent reviewers with a third adjudicator available for discrepancies. Residual tumour volumes were quantified by segmentation of postoperative 1mm slice MRI. Results: The FGS group was found to have: 80% complete resection (CR), 11% near-total resection (NTR), and 9% subtotal resection (STR). This compared favourably to the WLS respective rates of 67%, 6%, and 28%. Conclusions: For awake craniotomy protocol, the odds of complete resection were higher in the FGS group, compared to the WLS group (OR = 2; 95% CI 1.06, 2.93).