Ampo E, Medes-Silva AP, Goncalves V, et al. - Among older adults with late-life depression (LLD) and frailty, this inquiry was undertaken to assess the circulating cell-free mitochondrial DNA (ccf-mtDNA) levels, a marker of cellular stress and damage. It was hypothesized that higher ccf-mtDNA levels would be present in individuals with both frailty and LLD vs those with either condition in isolation. Participants were 53 older adults (Never Depressed+Robust (reference group, n=16), LLD+Robust (n=9), Never Depressed+Pre-frail/Frail (n=5), LLD+Pre-frail/Frail (n=23)). Findings revealed presence of increased markers of cellular damage and stress (i.e., ccf-mtDNA) in relation to co-existence of LLD and frailty. The observations indicate that cellular stress and mitochondrial dysfunction phenomena may be a common biological mechanism in both these conditions, thus, offering potential future opportunities for geroscience-guided interventions for these conditions.