BACKGROUND AND AIM:Atrial fibrillation (AF), the most common sustained arrhythmia in older adults, causes significant complications such as stroke, dementia, and decreased quality of life. Frailty is a geriatric syndrome that is associated with increased risk of poor clinical outcomes including falls, disability, and mortality. We aimed to investigate the relationship between AF and frailty and functionality in older adults. METHODS:A total of 123 patients 64 with AF and 59 with normal sinus rhythm were enrolled in the study with cross-sectional design. All patients underwent comprehensive geriatric assessment (CGA). Frailty status was assessed using Fried criteria and FRAIL scale. The brief Older People's Quality of Life questionnaire was applied for quality of life. Results of the laboratory tests were recorded and compared for both groups. RESULTS:Although the frequency of frailty status determined by the Fried criteria and the FRAIL scale was higher in the AF group, this difference was not statistically significant. However, it was found that there was a positive correlation between the European Heart Rhythm Association (EHRA) AF symptom score and frailty according to the FRAIL scale (Goodman and Kruskal gamma coefficient = 0.39, p = 0.020). Comorbidities and polypharmacy were more common in the AF group (p < 0.001, both). CGA revealed lower Lawton-Brody Instrumental Activities of Daily Living scores (p = 0.024), higher fall rates in the previous year (p = 0.016), and slower walking speed (p = 0.020) in the AF group. Total cholesterol, LDL, HDL, total protein, albumin, and prealbumin were lower; brain natriuretic peptide (BNP) and C-reactive protein (CRP) levels were higher in the AF group. CONCLUSIONS:EHRA AF symptom severity score is positively correlated with frailty. AF is associated with worse metabolic profile and clinical features on CGA that AF might be a frailty marker. Frailty should be investigated in AF patients.