Frailty is highly prevalent among patients with aortic stenosis (AS). Nonetheless, the impact of AS severity on frailty remains unclear. This study aimed to clarify the association between AS severity and frailty in this population.This retrospective study included consecutive patients with AS who were hospitalized as candidates for transcatheter aortic valve implantation (TAVI). The prevalence of frailty, N-terminal pro B-type natriuretic peptide (NT-proBNP) level, gait speed, and geriatric nutritional risk index (GNRI) were compared between patients with severe and those with very severe AS. We employed multiple logistic regression analysis to examine the association between AS severity and frailty.A total of 137 patients were included. The prevalence of frailty was not significantly different between the severe and very severe AS groups (31% versus 30%). Similarly, no significant differences between the groups were observed for gait speed and GNRI, whereas the NT-proBNP level was significantly higher in the very severe group than in the severe AS group (P < 0.01). In the multiple logistic regression analysis, AS severity was not associated with frailty; however, gait speed and GNRI showed significant association with frailty independently of age, sex, and heart failure (very severe AS: odds ratio [OR] 1.051, 95% confidence interval [CI] 0.439-2.517; low gait speed: OR 5.109, 95% CI 1.556-16.775; malnutrition: OR 2.841, 95% CI 1.145-7.049).These findings suggest that low-intensity exercise training and nutritional therapy may be necessary in addition to AS treatment for the management of frailty in this population.