['To examine the relationship between peripheral arterial disease (PAD) and atrial fibrillation (AF) in a population-based cohort study of older adults.', 'We examined the relationship between PAD and AF in 5143 participants (85% white, 43% male) in the Cardiovascular Health Study (CHS), a longitudinal, observational study of adults aged 65 years and older. Peripheral arterial disease was defined by abnormal ankle-brachial index (ABI) values (<1.0 or >1.4). Incident AF events were ascertained by self-reported history, study electrocardiograms, and hospitalization discharge records. Cox regression was used to compute hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between PAD and AF. Over a median follow-up of 11.7 years, a total of 1521 participants developed AF. The incidence rate (per 1000 person-years) of AF was higher in those with PAD (incidence rate = 32.9, 95% CI = 29.5, 36.7) than those without PAD (incidence rate = 23.3, 95% CI = 22.0, 24.6). In a multivariate Cox regression analysis, PAD was associated with an increased risk for AF (HR = 1.52, 95% CI = 1.34, 1.72). Each 0.1 decrease in the ABI was associated with a 6% increase in the risk for AF (HR = 1.06, 95% CI = 1.02, 1.10). The associations of high (>1.4) and low (<1.0) ABI values with AF were examined separately and were in the same direction as the main result for PAD (ABI < 1.0: HR = 1.24, 95% CI = 1.08, 1.42; ABI > 1.4: HR = 1.33, 95% CI = 0.95, 1.86).'] Is peripheral arterial disease associated with an increased risk of atrial fibrillation in the elderly?