Although preliminary data suggests that ibrutinib may increase risk of atrial fibrillation (AF), the incidence of AF in a general cohort of chronic lymphocytic leukemia (CLL) patients is unknown. We evaluated the prevalence of AF at CLL diagnosis and incidence of AF during follow-up in 2444 patients with newly diagnosed CLL. A prior history of AF was present at CLL diagnosis in 148 (6.1%). Among the 2292 patients without history of AF, 139 (6.1%) developed incident AF during follow-up (incidence approximately 1%/year). Older age (p < .0001), male sex (p = .01), valvular heart disease (p = .001), and hypertension (p = .04) were associated with risk of incident AF on multivariate analysis. A predictive model for developing incident AF constructed from these factors stratified patients into 4 groups with 10-year rates of incident AF ranging from 4% to 33% (p < .0001). This information provides context for interpreting rates of AF in CLL patients treated with novel therapies.