Background:Prevalence of atrial fibrillation (AF) is increasing as the world ages.AF is associated with higher risk of mortality and disease,including stroke,hypertension,heart failure,and dementia.Prevalence of AF differs with each population studied,and research on non-West populations and the oldest old is scarce.Methods:We used data from the 2012 wave of the Chinese Longitudinal Healthy Longevity Survey,a community-based study in eight longevity areas in China,to estimate AF prevalence in an elderly Chinese population (n =1418,mean age =85.6 years) and to identify risk factors.We determined the presence of AF in our participants using single-lead electrocardiograms.The weighted prevalence of AF was estimated in subjects stratified according to age groups (65-74,75-84,85-94,95 years and above) and gender.We used logistic regressions to determine the potential risk factors of AF.Results:The overall prevalence of AF was 3.5％; 2.4％ of men and 4.5％ of women had AF (P ＜ 0.05).AF was associated with weight extremes of being underweight or overweight/obese.Finally,advanced age (85-94 years),history of stroke or heart disease,low high-density lipoprotein levels,low triglyceride levels,and lack of regular physical activity were associated with AF.Conclusions:In urban elderly,AF prevalence increased with age (P ＜ 0.05),and in rural elderly,women had higher AF prevalence (P ＜ 0.05).Further exploration of population-specific risk factors is needed to address the AF epidemic.