Other ; UNLABELLED Obesity is a well-recognized risk factor for atrial fibrillation (AF), yet adiposity measures other than body mass index (BMI) have had limited assessment in relation to AF risk. We examined the associations of adiposity measures with AF in a biracial cohort of older adults. Given established racial differences in obesity and AF, we assessed for differences by black and white race in relating adiposity and AF. METHODS We analyzed data from 2,717 participants of the Health, Aging, and Body Composition Study. Adiposity measures were BMI, abdominal circumference, subcutaneous and visceral fat area, and total and percent fat mass. We determined the associations between the adiposity measures and 10-year incidence of AF using Cox proportional hazards models and assessed for their racial differences in these estimates. RESULTS In multivariable-adjusted models, 1-SD increases in BMI, abdominal circumference, and total fat mass were associated with a 13% to 16% increased AF risk (hazard ratio [HR] 1.14, 95% CI 1.02-1.28; HR 1.16, 95% CI 1.04-1.28; and HR 1.13, 95% CI 1.002-1.27). Subcutaneous and visceral fat areas were not significantly associated with incident AF. We did not identify racial differences in the associations between the adiposity measures and AF. CONCLUSION Body mass index, abdominal circumference, and total fat mass are associated with risk of AF for 10years among white and black older adults. Obesity is one of a limited number of modifiable risk factors for AF; future studies are essential to evaluate how obesity reduction can modify the incidence of AF.