Frailty is common in stroke, where it exerts disease- and treatment-modifying effects. However, there has been little work evaluating how frailty influences outcomes after percutaneous endoscopic gastrostomy (PEG) tube insertion. This study investigates the relationship between pre-stroke frailty and one-year mortality following PEG insertion. A pre-stroke frailty index (FI) was calculated for individuals with post-stroke dysphagia who underwent PEG insertion between March 2019 and February 2021. Mortality was recorded at one year, as well as instances of post-PEG pneumonia and discharge destination. Twenty-nine individuals underwent PEG insertion, eleven (37.9%) of whom died in the subsequent year. The mean (SD) FI for those who survived was 0.10 (0.09), compared to 0.27 (0.19) for those who died (p = 0.02). This remained significant after adjustment for age and sex, with each 0.1 increase in the FI independently associated with an increased odds of one-year mortality (aOR 1.39, 95% CI 1.17-1.67). There was no association between frailty and post-PEG pneumonia (0.12 (0.21) in those who aspirated versus 0.11 (0.18) in those who did not, p = 0.75). Pre-stroke frailty is associated with increased one-year mortality after PEG, a finding that may help inform shared clinical decision-making in complex decisions regarding PEG feeding.